[FIR] Do not enhance nullability for annotation interface field types.

Java annotation interface fields are constant declarations that can
have any Java type and are not restricted in the same way that
method return types are for annotation interfaces.

#KT-65482 Fixed

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/enhancement/SignatureEnhancement.kt

@@ -632,10 +632,19 @@ class FirSignatureEnhancement(
         defaultQualifiers: JavaTypeQualifiersByElementType?,
         predefinedEnhancementInfo: PredefinedFunctionEnhancementInfo?
     ): FirResolvedTypeRef {
-        val containerApplicabilityType = if (owner is FirJavaField)
+        val containerApplicabilityType = if (owner is FirJavaField) {
             AnnotationQualifierApplicabilityType.FIELD
-        else
+        } else {
             AnnotationQualifierApplicabilityType.METHOD_RETURN_TYPE
+        }
+        val forAnnotationMember = if (owner is FirJavaField) {
+            // Fields in annotation interfaces are constant declarations that can have any Java type.
+            // For example: public @interface MyApi { Integer field = -1; }
+            // Therefore, for such annotation interface fields, we use default Java type enhancement.
+            false
+        } else {
+            this.owner.classKind == ClassKind.ANNOTATION_CLASS
+        }
         return owner.enhance(
             overriddenMembers,
             owner,
@@ -644,7 +653,7 @@ class FirSignatureEnhancement(
             containerApplicabilityType,
             TypeInSignature.Return,
             predefinedEnhancementInfo?.returnTypeInfo,
-            forAnnotationMember = this.owner.classKind == ClassKind.ANNOTATION_CLASS
+            forAnnotationMember = forAnnotationMember
         )
     }