[FIR] Report missing ASSIGNMENT_TYPE_MISMATCH on functional types

^KT-45989

compiler/testData/diagnostics/tests/functionLiterals/kt56138.fir.kt

@@ -5,9 +5,9 @@ fun takeLambda1(f: String.() -> String) {}
 fun takeLambda2(f: String.(String) -> String) {}
 
 fun test_1() {
-    val x1: String.(String) -> String = { str, <!CANNOT_INFER_PARAMETER_TYPE!>str2<!> -> "this" }
+    val x1: String.(String) -> String = <!INITIALIZER_TYPE_MISMATCH!>{ str, <!CANNOT_INFER_PARAMETER_TYPE!>str2<!> -> "this" }<!>
     val x2: String.() -> String = { <!UNRESOLVED_REFERENCE!>it<!> }
-    val x3: String.() -> String = { <!CANNOT_INFER_PARAMETER_TYPE!>x<!> -> "x" }
+    val x3: String.() -> String = <!INITIALIZER_TYPE_MISMATCH!>{ <!CANNOT_INFER_PARAMETER_TYPE!>x<!> -> "x" }<!>
 }
 
 fun test_2() {