Replace fa-tag icon with GitLab SVG icon

What does this MR do?

I am not sure if this code is used at all since it's not linked anywhere in the UI. Accessing the URL directly and tweaking the code renders an almost blank page with just the icon and some text (see screenshot).

Test URL http://127.0.0.1:3000/gitlab-org/gitlab-shell/-/commit/e396f48abacdf12d153d00537ee76d6d300e42b2/branches

Screenshots

Note: This is the whole page, not cropped, i.e. there is no layout or any other content, just the icon and text.

After	Before

Does this MR meet the acceptance criteria?

Conformity

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

Availability 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
• 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:

• 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 #225926 (closed)