Make option dropdown button to match adjacent button

What does this MR do?

Make the option dropdown button to match the "Browse files" button adjacent to it. This will ensure the height of both buttons to be the same, create a more uniform design.

❌Issue

Note: the height difference

✅Result

Affected Area

• Repository > Commit Page > (select any commit)
• Note the "Options" dropdown button height matches the "Browser files" button next to it

Tested on:

• Chrome, IE11, Edge, Safari, Firefox

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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 #62144 (closed)