Separate UNSAFE_IMPLICIT_INVOKE_CALL diagnostics introduced (see KT-8252)

idea/testData/checker/SafeInvoke.kt

@@ -0,0 +1,8 @@
+class Rule(val apply: () -> Unit)
+
+fun foo() {
+    val rule: Rule? = Rule { }
+    rule?.<error descr="[UNSAFE_IMPLICIT_INVOKE_CALL] Reference has a nullable type (() -> kotlin.Unit)?, use explicit ?.invoke() to make function-like call instead">apply</error>()
+    val apply = rule?.apply
+    <error descr="[UNSAFE_IMPLICIT_INVOKE_CALL] Reference has a nullable type (() -> kotlin.Unit)?, use explicit ?.invoke() to make function-like call instead">apply</error>()
+}