Fix: Duplicates when click spam loading elements in FT (2/3)

[Shadorc]

Pull Request Type

• Bugfix
• Feature Implementation
• Documentation
• Other

Related issue

partially addresses #3541 (search page)

Description

Same remarks from #9383 apply here + this comment #9383 (comment).
Those MRs are independent and can be merged in any order.

Screenshots

2026-07-11.00-24-48.mp4

Testing

Manual:

1. Search any keywords with enough results to display "Fetch more results"
2. Click very fast on the "Fetch more results" button at the bottom of the search page
3. Check that the button disappears when the results are loading
4. Check that no duplicated videos are shown once loaded

Automatic:

1. Enable "Auto Load Next Page" setting
2. Search any keywords with enough results to display "Fetch more results"
3. Scroll to the bottom of the search page
4. Check that the button disappears when the results are loading
5. Check that no duplicated videos are shown once loaded

Desktop

• OS: Bazzite
• OS Version:
• FreeTube version: 0.24.1-beta