[SLC] SymbolLightClassForEnumEntry: improve implementation

^KT-54051
^KT-50241

compiler/testData/asJava/lightClasses/EnumEntry.fir.java

@@ -0,0 +1,17 @@
+static final class FirstEntry /* p.KotlinEnum.FirstEntry*/ extends p.KotlinEnum {
+  private final int firstEntryProp = 4 /* initializer type: int */;
+
+  private int variable = 1 /* initializer type: int */;
+
+   FirstEntry();//  .ctor()
+
+  @java.lang.Override()
+  public void abstractFun();//  abstractFun()
+
+  public final int getFirstEntryProp();//  getFirstEntryProp()
+
+  public final int getVariable();//  getVariable()
+
+  public final void firstEntryFun();//  firstEntryFun()
+
+}