Fir2Ir: more precise calculation of enum class modality

Use the same condition as in the already existing `createIrEnumEntry`
function (and as in psi2ir): enum class should be final unless there's
an enum entry with any declaration other than its constructor.

 #KT-57216

compiler/testData/ir/irText/classes/enumClassModality.fir.ir.txt

@@ -58,14 +58,14 @@ FILE fqName:<root> fileName:/enumClassModality.kt
         overridden:
           public final fun <get-ordinal> (): kotlin.Int declared in kotlin.Enum
         $this: VALUE_PARAMETER name:<this> type:kotlin.Enum<E of kotlin.Enum>
-  CLASS ENUM_CLASS name:TestFinalEnum2 modality:OPEN visibility:public superTypes:[kotlin.Enum<<root>.TestFinalEnum2>]
+  CLASS ENUM_CLASS name:TestFinalEnum2 modality:FINAL visibility:public superTypes:[kotlin.Enum<<root>.TestFinalEnum2>]
     $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:<root>.TestFinalEnum2
     CONSTRUCTOR visibility:private <> (x:kotlin.Int) returnType:<root>.TestFinalEnum2 [primary]
       VALUE_PARAMETER name:x index:0 type:kotlin.Int
       BLOCK_BODY
         ENUM_CONSTRUCTOR_CALL 'public constructor <init> (name: kotlin.String, ordinal: kotlin.Int) [primary] declared in kotlin.Enum'
           <E>: <root>.TestFinalEnum2
-        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS ENUM_CLASS name:TestFinalEnum2 modality:OPEN visibility:public superTypes:[kotlin.Enum<<root>.TestFinalEnum2>]'
+        INSTANCE_INITIALIZER_CALL classDescriptor='CLASS ENUM_CLASS name:TestFinalEnum2 modality:FINAL visibility:public superTypes:[kotlin.Enum<<root>.TestFinalEnum2>]'
     PROPERTY name:x visibility:public modality:FINAL [val]
       FIELD PROPERTY_BACKING_FIELD name:x type:kotlin.Int visibility:private [final]
         EXPRESSION_BODY