[K/JS] Deprecate external enum declarations

^KT-57254 Fixed

compiler/testData/diagnostics/testsWithJsStdLib/native/inheritance.kt

@@ -1,4 +1,5 @@
 // FIR_IDENTICAL
+// !DIAGNOSTICS: +ENUM_CLASS_IN_EXTERNAL_DECLARATION_WARNING
 open class A
 
 interface I
@@ -11,10 +12,10 @@ external class <!EXTERNAL_TYPE_EXTENDS_NON_EXTERNAL_TYPE!>D<!> : B, I
 
 external interface <!EXTERNAL_TYPE_EXTENDS_NON_EXTERNAL_TYPE!>K<!> : I
 
-external enum class E {
+external enum class <!ENUM_CLASS_IN_EXTERNAL_DECLARATION_WARNING!>E<!> {
     X
 }
 
-external enum class <!EXTERNAL_TYPE_EXTENDS_NON_EXTERNAL_TYPE!>F<!> : I {
+external enum class <!ENUM_CLASS_IN_EXTERNAL_DECLARATION_WARNING, EXTERNAL_TYPE_EXTENDS_NON_EXTERNAL_TYPE!>F<!> : I {
     X
 }