Refactor WebIDE error message to use GlAlert

What does this MR do?

Rewrite the template used in the WebIDE error-message component to make use of GlAlert from @gitlab/ui. This change also resolves the broken looking action link referenced in #36852 (closed).

Screenshots

State	Before	After
Error message without action, dismissible (Note: this is a contrived example as setErrorMessage is never dispatched without an action property)
Error message with action
Error message with action (loading)

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

Closes #36854 (closed) and #36852 (closed)