FIR checker: improve diagnostics message for SEALED_INHERITOR_IN_DIFFERENT_PACKAGE

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -452,8 +452,6 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
     }
     add(FirErrors.SEALED_INHERITOR_IN_DIFFERENT_PACKAGE) { firDiagnostic ->
         SealedInheritorInDifferentPackageImpl(
-            firDiagnostic.a,
-            firDiagnostic.b,
             firDiagnostic as FirPsiDiagnostic,
             token,
         )

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -343,8 +343,6 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
 
     abstract class SealedInheritorInDifferentPackage : KtFirDiagnostic<KtTypeReference>() {
         override val diagnosticClass get() = SealedInheritorInDifferentPackage::class
-        abstract val subclassPackage: FqName
-        abstract val basePackage: FqName
     }
 
     abstract class SealedInheritorInDifferentModule : KtFirDiagnostic<KtTypeReference>() {

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -523,8 +523,6 @@ internal class SealedSupertypeInLocalClassImpl(
 }
 
 internal class SealedInheritorInDifferentPackageImpl(
-    override val subclassPackage: FqName,
-    override val basePackage: FqName,
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,
 ) : KtFirDiagnostic.SealedInheritorInDifferentPackage(), KtAbstractFirDiagnostic<KtTypeReference> {