Fix pipeline status update in pipeline editor

What does this MR do?

Related to #335074 (closed).

We refactored the pipeline editor to fetch the commitSha using graphql. This fixes a bug related to the refactor where the pipeline status does not update correctly when committing changes to the current branch.

When committing a new branch, it's possible that the pipeline data is not yet ready when the vue app fetches it, so we poll for the data until it is received. This is also the case for committing changes to the current branch (it seems we're fetching too early).

Since the bug fix is for a change that was released in the current milestone, no changelog trailers were added.

Screenshots or Screencasts

Committing to current branch

How to setup and validate locally (strongly suggested)

1. Go to the Pipeline Editor in CI/CD > Editor,
2. At the bottom of the page, submit a commit to the same branch you are in.
3. Wait a few seconds and verify that the pipeline status is updated with the new pipeline and commit.

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 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.)