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()
 }