Revert "Temporary: make PRE_RELEASE_CLASS a warning in both K1/K2 (KT-66551)"

This reverts commit a0cb713d19.
#KT-66551 Fixed

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -1805,7 +1805,7 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
             parameter<String>("presentableString")
             parameter<IncompatibleVersionErrorData<*>>("incompatibility")
         }
-        val PRE_RELEASE_CLASS by warning<PsiElement> {
+        val PRE_RELEASE_CLASS by error<PsiElement> {
             parameter<String>("presentableString")
         }
         val IR_WITH_UNSTABLE_ABI_COMPILED_CLASS by error<PsiElement> {

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -895,7 +895,7 @@ object FirErrors {
 
     // Compatibility issues
     val INCOMPATIBLE_CLASS: KtDiagnosticFactory2<String, IncompatibleVersionErrorData<*>> by error2<PsiElement, String, IncompatibleVersionErrorData<*>>()
-    val PRE_RELEASE_CLASS: KtDiagnosticFactory1<String> by warning1<PsiElement, String>()
+    val PRE_RELEASE_CLASS: KtDiagnosticFactory1<String> by error1<PsiElement, String>()
     val IR_WITH_UNSTABLE_ABI_COMPILED_CLASS: KtDiagnosticFactory1<String> by error1<PsiElement, String>()
 
     // Builder inference

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirNonSuppressibleErrorNames.kt

@@ -578,6 +578,7 @@ val FIR_NON_SUPPRESSIBLE_ERROR_NAMES: Set<String> = setOf(
     "MIXING_FUNCTIONAL_KINDS_IN_SUPERTYPES",
     "MULTIPLE_LABELS_ARE_FORBIDDEN",
     "INCOMPATIBLE_CLASS",
+    "PRE_RELEASE_CLASS",
     "IR_WITH_UNSTABLE_ABI_COMPILED_CLASS",
     "BUILDER_INFERENCE_STUB_RECEIVER",
     "BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION",