Make `Job`, `Bridge` and `Default` to be truly inheritable

What does this MR do?

This ensures that all entries that are added to Job/Bridge are considered to be inheritable.

This adds a easy to mixin that ensures the consistency between all types and keys.

Closes #34518 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry

• Documentation created/updated or follow-up review issue created

• Code review guidelines

• Merge request performance guidelines

• Style guides

• Database guides

• Separation of EE specific content

• Label as security and @ mention @gitlab-com/gl-security/appsec

• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods

• Security reports checked/validated by a reviewer from the AppSec team