Remove some usages of FirBasedSymbol

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/deserialization/KotlinDeserializedJvmSymbolsProvider.kt

@@ -409,8 +409,7 @@ class KotlinDeserializedJvmSymbolsProvider(
 
 
     private fun findRegularClass(classId: ClassId): FirRegularClass? =
-        @Suppress("UNCHECKED_CAST")
-        (getClassLikeSymbolByFqName(classId) as? FirBasedSymbol<FirRegularClass>)?.fir
+        getClassLikeSymbolByFqName(classId)?.fir as? FirRegularClass
 
     override fun getAllCallableNamesInClass(classId: ClassId): Set<Name> =
         getClassDeclarations(classId)

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

@@ -242,7 +242,7 @@ internal fun ConeKotlinType.lexicalCastFrom(session: FirSession, value: String):
         else -> return null
     }
     val lookupTag = lookupTagBasedType.lookupTag
-    val firElement = (lookupTag.toSymbol(session) as? FirBasedSymbol<*>)?.fir
+    val firElement = lookupTag.toSymbol(session)?.fir
     if (firElement is FirRegularClass && firElement.classKind == ClassKind.ENUM_CLASS) {
         val name = Name.identifier(value)
         val firEnumEntry = firElement.declarations.filterIsInstance<FirEnumEntry>().find { it.name == name }