Always generate append_X_pack calls if not in development

[Judahmeek]

Summary

Instead of creating an append_X_pack call conditional on the existence of the generated pack entrypoint, the new logic will always create the append_X_pack call for the component as long as the component's render option's auto_load_bundle is true in test or production environments.

In the development environment, however, a missing generated pack entrypoint will result in a raised error message.

Pull Request checklist

• Add/update test to cover these changes
• Update documentation
• Update CHANGELOG file

Other Information

Remove this paragraph and mention any other important and relevant information such as benchmarks.

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This change is 

[justin808]

@Judahmeek any changelog entry?

[justin808]

LGTM.

Please add changelog and merge, @Judahmeek