Replace Runner Page Title with Runner’s Hash

What does this MR do?

This MR replaces the page title and breadcrumb of the individual runner page in the admin section with the the runner’s short hash (8 character long).

Related to #257888 (closed).

Screenshots

Description?	Before	After
blank
e.g. high performance runner on AWS

Relevant changes in the images (both: Runners to display name):

• the title of the tab
• the most right breadcrumb item

Steps to test

1. Go to the admin section
2. Create a runner if you don't have on set up

5. See that the title and breadcrumb are equal to the runner's token (8 character string)

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