Format graphql files with prettier

What does this MR do?

This switches on prettier for graphql files.

Issue: #227280 (closed)

Guide for merging this with minimal conflits

1. Immediately before merge, check out branch locally and merge/rebase in the latest master.
2. If there are conflicts:
   1. Reset to the latest master git reset --hard origin/master
   2. Re-apply the docs/tooling changes. git cherry-pick 59727f592b978fa55b9714b2791e28861fc9983e a7d7f27632680775c585ae2696db361e8a25d4b5 82e57c26f1c7538fcfe23d72615f11aa96235eac
   3. Re-run prettier yarn prettier-all-save
   4. Add and commit these changes git add . && git commit -m 'Format graphql files with prettier'
   5. Check that no non-graphql files were included.
3. Push to the branch if there are changes.
4. Check the changes one last time.
5. Merge!

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [n/a] Database guides
• Separation of EE specific content

Availability and Testing

• [n/a] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [n/a] Tested in all supported browsers
• [n/a] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [n/a] Label as security and @ mention @gitlab-com/gl-security/appsec
• [n/a] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [n/a] Security reports checked/validated by a reviewer from the AppSec team