Fix Search Settings Placeholder Text

What does this MR do and why?

Currently, the search in the settings area only searches the page the user is on. Search settings implies that the search works for the entire settings area, not just the page. This MR is to adjust the placeholder text to Search page, which more accurately describes the action.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. View the settings page in any project.
2. Ensure the placeholder text now says Search page.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.