FIR: Change semantics for combination of safe calls and operators

^KT-41034 Fixed

compiler/tests-spec/testData/diagnostics/linked/expressions/prefix-expressions/prefix-decrement-expression/p-4/neg/1.1.fir.kt

@@ -15,7 +15,7 @@ class A() {
 
 fun case1() {
     var b: Case1? = Case1()
-    <!UNSAFE_CALL!>--<!>b?.a
+    --b?.a
 }
 
 

compiler/tests-spec/testData/diagnostics/linked/expressions/prefix-expressions/prefix-increment-expression/p-4/neg/1.1.fir.kt

@@ -15,7 +15,7 @@ class A() {
 
 fun case1() {
     var b: Case1? = Case1()
-    <!UNSAFE_CALL!>++<!>b?.a
+    ++b?.a
 }