KT-64832 KT-61032 [FIR] Correctly handle extension receiver from implicit invoke calls in UnusedChecker

- use `FirImplicitInvokeCall` instance check to detect implicit calls,
it is cleaner than checking particular resolve type and "invoke" name
- reuse `visitQualifiedAccesses` to update the CFG instead of manually
searching through the `localProperties` (because it didn't work in the
case of overloads)

^KT-64832 Fixed
^KT-61032 Fixed

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeCustomTypeExt.kt

@@ -3,7 +3,7 @@ class Foo
 operator fun Foo.invoke() {}
 
 fun foo() {
-    val <!UNUSED_VARIABLE!>x<!> = Foo()
+    val x = Foo()
 
     x()
 }

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeCustomTypeMember.kt

@@ -3,7 +3,7 @@ class Foo {
 }
 
 fun foo() {
-    val <!UNUSED_VARIABLE!>x<!> = Foo()
+    val x = Foo()
 
     x()
 }

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeKFunction.kt

@@ -2,7 +2,7 @@
 import kotlin.reflect.KFunction1
 
 fun foo(action: KFunction1<String, Int>): Int {
-    val <!UNUSED_VARIABLE!>localAction<!> = action
+    val localAction = action
 
     return localAction("hello")
 }

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeKFunctionFromMethodReference.kt

@@ -2,7 +2,7 @@
 fun foo(): Int {
     fun action(s: String): Int = s.toInt()
 
-    val <!UNUSED_VARIABLE!>localAction<!> = ::action
+    val localAction = ::action
 
     return localAction("hello")
 }

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeKSuspendFunction.kt

@@ -2,7 +2,7 @@
 import kotlin.reflect.KSuspendFunction1
 
 suspend fun foo(action: KSuspendFunction1<String, Int>): Int {
-    val <!UNUSED_VARIABLE!>localAction<!> = action
+    val localAction = action
 
     return localAction("hello")
 }

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeOverload2.kt

@@ -1,8 +1,8 @@
 fun foo() {
-    val x = fun(s: String) {}
+    val <!UNUSED_VARIABLE!>x<!> = fun(s: String) {}
 
     fun nested() {
-        val <!UNUSED_VARIABLE!>x<!> = fun(i: Int) {}
+        val x = fun(i: Int) {}
 
         x(10)
     }

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/unused/invokeSuspend.kt

@@ -1,5 +1,5 @@
 suspend fun foo(action: suspend () -> Unit) {
-    val <!UNUSED_VARIABLE!>x<!> = action
+    val x = action
 
     x()
 }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/extended/UnusedChecker.kt

@@ -20,20 +20,16 @@ import org.jetbrains.kotlin.fir.analysis.checkers.isIterator
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
 import org.jetbrains.kotlin.fir.expressions.*
-import org.jetbrains.kotlin.fir.references.resolved
 import org.jetbrains.kotlin.fir.references.toResolvedPropertySymbol
 import org.jetbrains.kotlin.fir.resolve.dfa.cfg.*
 import org.jetbrains.kotlin.fir.symbols.SymbolInternals
-import org.jetbrains.kotlin.fir.symbols.impl.FirFunctionSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
 import org.jetbrains.kotlin.fir.symbols.lazyResolveToPhase
-import org.jetbrains.kotlin.fir.types.coneType
-import org.jetbrains.kotlin.fir.types.isBasicFunctionType
 import org.jetbrains.kotlin.name.SpecialNames
 
 object UnusedChecker : AbstractFirPropertyInitializationChecker() {
     override fun analyze(data: PropertyInitializationInfoData, reporter: DiagnosticReporter, context: CheckerContext) {
-        val ownData = ValueWritesWithoutReading(context.session, data.properties).getData(data.graph)
+        val ownData = ValueWritesWithoutReading(data.properties).getData(data.graph)
         data.graph.traverse(CfaVisitor(ownData, reporter, context))
     }
 
@@ -149,7 +145,6 @@ object UnusedChecker : AbstractFirPropertyInitializationChecker() {
     }
 
     private class ValueWritesWithoutReading(
-        private val session: FirSession,
         private val localProperties: Set<FirPropertySymbol>
     ) : PathAwareControlFlowGraphVisitor<VariableStatusInfo>() {
         companion object {
@@ -274,16 +269,16 @@ object UnusedChecker : AbstractFirPropertyInitializationChecker() {
             data: PathAwareVariableStatusInfo
         ): PathAwareVariableStatusInfo {
             val dataForNode = visitNode(node, data)
-            val reference = node.fir.calleeReference.resolved ?: return dataForNode
-            val functionSymbol = reference.resolvedSymbol as? FirFunctionSymbol<*> ?: return dataForNode
-            val symbol = if (functionSymbol.callableId.callableName.identifier == "invoke") {
-                localProperties.find { it.name == reference.name && it.resolvedReturnTypeRef.coneType.isBasicFunctionType(session) }
-            } else null
-            symbol ?: return dataForNode
 
-            val status = VariableStatus.READ
+            val functionCall = node.fir
-            status.isRead = true
+            if (functionCall is FirImplicitInvokeCall) {
-            return update(dataForNode, symbol) { status }
+                val invokeReceiver = functionCall.explicitReceiver as? FirQualifiedAccessExpression
+                if (invokeReceiver != null) {
+                    return visitQualifiedAccesses(dataForNode, invokeReceiver)
+                }
+            }
+
+            return dataForNode
         }
 
         private fun update(