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

[Shadorc]

@PikachuEXE What do you think about removing "Fetching results. Please wait" toast message here too without adding a loading message, to be consistent with the other MR?
This is the last place where "Please wait" message is shown

[PikachuEXE]

Put that into another PR coz there is also There are no more results for this search and making any change make this harder to be merged