[Bug] Channel: parameter search returns no results

[chocmake]

Describe the bug
Using the channel: parameter for queries no longer returns results.

Steps to Reproduce

1. Visit a channel and copy its channel ID from the URL.
2. In the search box enter channel:<channelID> <query>
3. Observe no results found.

Example: this channel is all about antennas. However querying antenna with such a channel search returns no results (Snopyta example query).

According to my history the last time this parameter search worked was 2023-01-21 (unsure what Invidious version the instance I was using was on at that time though).

Additional context
Noticed on both Snopyta (2023.01.24-9a9f8231) and Yewtu.be (2023.01.28-71f980b) instances.

[ChunkyProgrammer]

It seems like you may need to have a space after the colon for it to work (not sure if this was always the case)

I also noticed that the link your provided did not properly encode the ":" character which can also be part of the issue.
With the unencoded colon, it fails:
https://invidious.snopyta.org/search?q=channel:UCHqwzhcFOsoFFh33Uy8rAgQ%20antenna

And this should work (notice the %3A):
https://invidious.snopyta.org/search?q=channel%3A+UCHqwzhcFOsoFFh33Uy8rAgQ%20antenna

[chocmake]

https://invidious.snopyta.org/search?q=channel%3A+UCHqwzhcFOsoFFh33Uy8rAgQ%20antenna

This doesn't return results from the specified channel though, just generic search results containing the raw channel ID and query included. Fwiw, the original syntax was non spaces, eg seen in an earlier bug report of mine (#3148).

If we use the colon escaped encoding (without the space, as per original syntax) it similarly doesn't return results for the specified channel (example).

[ChunkyProgrammer]

Would like to add that this issue also affects the API

Ex:
https://yt.artemislena.eu/api/v1/channels/search/UCHqwzhcFOsoFFh33Uy8rAgQ?q=antenna

[SamantazFox]

That's possible that Youtube changed their channel search