Disable commenting on symlinks in symlink-related files

What does this MR do?

For #223076 (closed).

While we do the underlying work to make it possible to comment on symlink-related files (symlinks, deleted symlinks, files replaced by symlinks, symlinks replaced by files), we need to fix the UI that's broken when a user tries to leave a comment on one of these types of files.

This MR just disables the comment button in the correct scenarios and updates the tooltip text to indicate why.

Screenshots

Scenario	Screenshot
Normal Files
Replaced symlinks, symlinks that replace files
Files replaced by symlink, files that replace symlinks

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