[FIR, IR] Refactor: restructure ExpectActualCompatibility class hierarchy

KT-62590 is in progress

This commit is pure refactoring.
- No tests changed their behaviour
- Semantics isn't changed

Review: https://jetbrains.team/p/kt/reviews/12750/timeline

analysis/analysis-api-fir/analysis-api-fir-generator/src/org/jetbrains/kotlin/analysis/api/fir/generator/HLDiagnosticConverter.kt

@@ -373,7 +373,7 @@ internal object FirToKtConversionCreator {
         ClassId::class,
         FirModuleData::class,
         ExpectActualCompatibility::class,
-        ExpectActualCompatibility.Incompatible::class,
+        ExpectActualCompatibility.MismatchOrIncompatible::class,
         ExpectActualAnnotationsIncompatibilityType::class,
         DeprecationInfo::class,
         ApiVersion::class,