[FIR] Fix inconsistent RETURN_TYPE_MISMATCH and TYPE_MISMATCH reporting on functions and properties

^KT-51203 Fixed

compiler/fir/analysis-tests/testData/resolve/diagnostics/returnTypeMismatchOnOverride.kt

@@ -57,7 +57,7 @@ open class J() : S() {
 }
 
 open class Base<T : X, Z : T> {
-    open fun kek(): Z = <!RETURN_TYPE_MISMATCH, TYPE_MISMATCH!>Z()<!>
+    open fun kek(): Z = <!RETURN_TYPE_MISMATCH!>Z()<!>
 }
 
 open class GoodDerrived : Base<Y, W>() {

compiler/fir/analysis-tests/testData/resolve/expresssions/invoke/threeReceiversCorrect.kt

@@ -3,7 +3,7 @@ class C
 class B
 
 class A {
-    val B.foo: C.() -> Unit get() = null
+    val B.foo: C.() -> Unit get() = <!NULL_FOR_NONNULL_TYPE!>null<!>
 }
 
 fun <T, R> with(arg: T, f: T.() -> R): R = arg.f()

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierChecker.kt

@@ -81,7 +81,7 @@ open class J {
         }
 
     var bar = <!PROPERTY_INITIALIZER_NO_BACKING_FIELD!>0<!>
-        get() = 3.1415926535
+        get() = <!RETURN_TYPE_MISMATCH!>3.1415926535<!>
         set(value) {}
 }