[FIR] Fix processing constructors of sealed classes

- Allow declaring protected constructors in sealed classes
- Make default visibility of sealed class constructor `protected`

KT-44861
KT-44865

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

@@ -260,8 +260,8 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
-    add(FirErrors.NON_PRIVATE_CONSTRUCTOR_IN_SEALED) { firDiagnostic ->
-        NonPrivateConstructorInSealedImpl(
+    add(FirErrors.NON_PRIVATE_OR_PROTECTED_CONSTRUCTOR_IN_SEALED) { firDiagnostic ->
+        NonPrivateOrProtectedConstructorInSealedImpl(
             firDiagnostic as FirPsiDiagnostic<*>,
             token,
         )

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

@@ -190,8 +190,8 @@ sealed class KtFirDiagnostic<PSI: PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = NonPrivateConstructorInEnum::class
     }
 
-    abstract class NonPrivateConstructorInSealed : KtFirDiagnostic<PsiElement>() {
-        override val diagnosticClass get() = NonPrivateConstructorInSealed::class
+    abstract class NonPrivateOrProtectedConstructorInSealed : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = NonPrivateOrProtectedConstructorInSealed::class
     }
 
     abstract class CyclicConstructorDelegationCall : KtFirDiagnostic<PsiElement>() {

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

@@ -299,10 +299,10 @@ internal class NonPrivateConstructorInEnumImpl(
     override val firDiagnostic: FirPsiDiagnostic<*> by weakRef(firDiagnostic)
 }
 
-internal class NonPrivateConstructorInSealedImpl(
+internal class NonPrivateOrProtectedConstructorInSealedImpl(
     firDiagnostic: FirPsiDiagnostic<*>,
     override val token: ValidityToken,
-) : KtFirDiagnostic.NonPrivateConstructorInSealed(), KtAbstractFirDiagnostic<PsiElement> {
+) : KtFirDiagnostic.NonPrivateOrProtectedConstructorInSealed(), KtAbstractFirDiagnostic<PsiElement> {
     override val firDiagnostic: FirPsiDiagnostic<*> by weakRef(firDiagnostic)
 }