refactor(ngcc): rework undecorated parent migration (#33362)

Previously, the (currently disabled) undecorated parent migration in
ngcc would produce errors when a base class could not be determined
statically or when a class extends from a class in another package. This
is not ideal, as it would cause the library to fail compilation without
a workaround, whereas those problems are not guaranteed to cause issues.

Additionally, inheritance chains were not handled. This commit reworks
the migration to address these limitations.

PR Close #33362

packages/compiler-cli/src/ngtsc/diagnostics/src/code.ts

@@ -75,17 +75,6 @@ export enum ErrorCode {
    */
   NGCC_MIGRATION_DECORATOR_INJECTION_ERROR = 7001,
 
-  /**
-   * Raised when ngcc tries to decorate a base class that was imported from outside the package.
-   */
-  NGCC_MIGRATION_EXTERNAL_BASE_CLASS = 7002,
-
-  /**
-   * Raised when ngcc tries to migrate a class that is extended from a dynamic base class
-   * expression.
-   */
-  NGCC_MIGRATION_DYNAMIC_BASE_CLASS = 7003,
-
   /**
    * An element name failed validation against the DOM schema.
    */