Resolve "Export frontend fixtures as pipeline artifact"

What does this MR do?

This MR aims to clean up our frontend fixtures in such a way that they can be exported as pipeline artifacts for analysis in the event that a karma or jest job fails.

Changes:

• resolve annoying deprecation warnings when generating fixtures by changing be_success -> be_successful
• move fixture source files from spec/javascripts/fixtures to spec/frontend/fixtures as we are transitioning away from karma
• renames rake task from karma:fixtures to frontend:fixtures (closes #59166 (closed))
• place generated fixtures into tmp/tests/frontend/fixtures instead of placing them next to their source files. removing generated fixtures can now be done with rm -rf tmp/tests/frontend rather than carefully removing the non-source-controlled files from the /spec/javascripts/fixtures subdirectories.
• simplify the paths used by karma to access fixture files within tests by using proxies
• (EE-port) remove duplicated static fixtures within ee directory (gitlab-org/gitlab-ee!14751)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

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:

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

Closes #64722 (closed)