Fix instantiated generic mixin declaration emit (#19144)

* Fix #18545, dont use declared type of class expression

* Accept API Baselines

* Add thus far unused flag from node builder

* Accept baseline update

src/compiler/checker.ts

@@ -3398,7 +3398,7 @@ namespace ts {
                     else if (flags & TypeFormatFlags.WriteClassExpressionAsTypeLiteral &&
                              type.symbol.valueDeclaration &&
                              type.symbol.valueDeclaration.kind === SyntaxKind.ClassExpression) {
-                        writeAnonymousType(getDeclaredTypeOfClassOrInterface(type.symbol), flags);
+                        writeAnonymousType(type, flags);
                     }
                     else {
                         // Write the type reference in the format f<A>.g<B>.C<X, Y> where A and B are type arguments