Plugins: Hide search form on Favorites tab

[manishdhorepatil-art]

The plugin search form should not be displayed on the Favorites tab where it is not applicable. This change prevents the search form from rendering when viewing favorite plugins, reducing UI confusion and aligning with expected behavior.

Fixes #65026

Ticket track -https://core.trac.wordpress.org/ticket/65026

Go to Plugins → Add New

Click Favorites tab

1. Verify search form is hidden
   Click Featured tab

2. Verify search form is visible
   Click Popular tab

3.Verify search form is visible
Click Recommended tab

4.Verify search form is visible

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[github-actions]

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