FIR: Refine callable reference resolution in assignment position

synthetic_select<() -> T>(::foo) form allows to select better candidate
than synthetic_select(::foo) with expect type `() -> T`

compiler/fir/analysis-tests/testData/resolveWithStdlib/diagnostics/initializerTypeMismatchChecker/functionType.kt

@@ -11,7 +11,7 @@ package testsCase1
 class Case() {
     fun case(v: V) {
         // InitializerTypeMismatchChecker bug
-        val va: () -> String = <!INITIALIZER_TYPE_MISMATCH!>(V)::a<!>
+        val va: () -> String = (V)::a
 
         val vb: () -> String = (V)::b