[FIR] Properly prohibit access to enum companion in enum entry initialization section

^KT-57456 Fixed
KT-57608

compiler/fir/analysis-tests/testData/resolve/fromBuilder/enums.kt

@@ -23,7 +23,7 @@ enum class Planet(val m: Double, internal val r: Double) {
         }
     };
 
-    val g: Double = <!UNINITIALIZED_VARIABLE!>G<!> * m / (r * r)
+    val g: Double = <!UNINITIALIZED_ENUM_COMPANION!>G<!> * m / (r * r)
 
     abstract fun sayHello()