FIR: add UnsafeCall resolution diagnostics

Previously unsafe call is reported as part of InapplicableWrongReceiver.
This makes it difficult for the downstream checkers to report different
diagnostics.

compiler/fir/analysis-tests/testData/resolveWithStdlib/contracts/fromSource/good/returnsImplies/eqNotEq.fir.txt

@@ -29,7 +29,7 @@ FILE: eqNotEq.kt
                 R|<local>/x|.R|kotlin/String.length|
             }
             else ->  {
-                R|<local>/x|.<Inapplicable(INAPPLICABLE_WRONG_RECEIVER): kotlin/String.length>#
+                R|<local>/x|.<Inapplicable(UNSAFE_CALL): kotlin/String.length>#
             }
         }
 

compiler/fir/analysis-tests/testData/resolveWithStdlib/contracts/fromSource/good/returnsImplies/receivers.fir.txt

@@ -33,7 +33,7 @@ FILE: receivers.kt
             this@R|special/anonymous|.R|/myRequireNotNull|()
         }
         )
-        R|<local>/x|.<Inapplicable(INAPPLICABLE_WRONG_RECEIVER): /foo>#()
+        R|<local>/x|.<Inapplicable(UNSAFE_CALL): /foo>#()
     }
     public final fun test_4(x: R|A?|): R|kotlin/Unit| {
         R|kotlin/with|<R|A?|, R|kotlin/Unit|>(R|<local>/x|, <L> = with@fun R|A?|.<anonymous>(): R|kotlin/Unit| <inline=Inline, kind=EXACTLY_ONCE>  {