Fix security dashboard project selector pagination

What does this MR do?

It fixes a pagination issue with the instance level security dashboard's project selector.

Steps to reproduce:

1. Browse to https://gitlab.com/-/security
2. Click 'Add projects'
3. Search for 'git'

This issue was introduced by a recent change: !26138 (49b4ed88)

Screenshots

before	after
before	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

Related to #196526 (closed)