Fix obscured arrow in runner recent searches

What does this MR do?

The regex substitution for old buttons in app/views/admin/ added gl-button to the recent searches dropdown in the Admin > Runners section causing a UI Bug that obscured the chevron.

Bug: #293974 (closed)

Other similar buttons for searches are not using applying the gl-button, so this change is aimed at UI consistency.

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