Fix signature badge popover not showing on Firefox

What does this MR do?

Fix signature badge popover not showing on Firefox and Safari.

This issue is reproducible on:

• Firefox 72.0.2
• Safari 13.0.5

Steps to reproduce

List commits page

1. Navigate to the list commits page (e.g. https://gitlab.com/gitlab-org/gitlab/-/commits/master)
2. Find a commit with Verified or Unverified signature badge
3. Click on the badge to view more details
4. The badge popover does not show on Firefox and Safari. It works in Chrome.

View commit page

1. Navigate to the view commit page (e.g. f0897cb5)
2. Click on the badge located on the header section to view more details
3. The badge popover does not show on Firefox and Safari. It works in Chrome.

Project tree view page

1. Navigate to the project tree view page (e.g. https://gitlab.com/gitlab-org/gitlab/-/tree/master/ee/spec/services/ee/users)
2. Click on the badge located on the most recent commit section to view more details
3. The badge popover does not show on Firefox and Safari. It works in Chrome.

Screenshots

List commits page (after)

View commit page (after)

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