Clarify verbiage for stuck jobs error message

What does this MR do?

Closes #29994 (closed)

Updates the error message that is displayed when a tagged job is stuck. This change aims to more clearly indicate that a runner may not be available, but is not necessarily offline. This change also clarifies that the link in the error message is taking you to the specific project's CI/CD settings pages.

Screenshots

Current look/verbiage:

Proposed changes:

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

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