Step 1 - Clean up `commit_sidebar/form_spec` and commit constants

• Step 1 - Clean up commit_sidebar/form_spec and commit constants
• Step 2 - Add alert and disable when cannot push code in IDE

What does this MR do?

This MR does a bit of clean up which helps support !51710 (merged).

• Moves commit_sidebar/form_spec.js to @vue/test-utils.
• Cleans up a unusual default export pattern for multiple named exports.
• Adds stubbed methods to our stub_component helper which helps in stubbing GlModal since we call .show() sometimes.

Does this MR meet the acceptance criteria?

Conformity

• [ ] Changelog entry Not needed
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

References

Related to #213581 (closed)