Remove commit sha from being passed to the pipeline editor

What does this MR do?

For #335074 (closed). Follow up to !67542 (merged).

We recently did a refactor on the pipeline editor so that it receives the commitSha data from the backend through graphql instead of rails. This MR is to remove the part where we pass the data from rails to the vue app, as it is no longer necessary.

Screenshots or Screencasts

Features affected by commit sha:

• pipeline status should update to the correct pipeline/commit when committing branches
• pipeline status should update to the correct pipeline/commit when switching branches
• include config should reflect the config in the current branch

No new changes are added to the pipeline editor, so everything should work as before.

Commit Sha Tests

How to setup and validate locally

To verify that nothing is broken, you can follow the validation steps detailed in !67542 (merged).

Does this MR meet the acceptance criteria?

Conformity

• [-] I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• [-] I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)