Fix Peertube account subscribers extraction

[AudricV]

Fix Peertube account subscribers extraction by adding the subscribers of all channels of an account to the subscribers of this account.

Minimal subscriber count for Framasoft account has been increased to 750 in the test.

• I carefully read the contribution guidelines and agree to them.

[TobiGr]

I already took a look at that one, too. But there seems to be a huge difference between the API result for this channel and the follower count on the website: 491 vs 952
To be honest, I have no idea, why we get different data here.

[AudricV]

When I loaded the first time the website, it shows 491 followers first briefly and after 952. I don't understand why.

[B0pol]

I GOT IT

I noticed something : it is what we've previously called a "parent channel". The channel, owner channel has 491 subscribers, but all the different sub-channels, video-channels have 461 subscribers if you sum them all. That makes 952 subscribers

The request that gives 491: https://framatube.org/api/v1/accounts/framasoft

To have the full subscriber count you have to make another request to get video channels (add /video-channels)
https://framatube.org/api/v1/accounts/framasoft/video-channels
and add all subscribers count.

That's what the web client does according to a quick look at the network tab of devtools

[AudricV]

@B0pol I implement what you said, this should be done now.
Tests are failing but it's not related to the subscribers extraction.

[Stypox]

@B0pol @TobiGr could you merge this if you think it's ok?

[TobiGr]

Looks good to me. We should add a comment about what is done here and why it is done, so other people going through the code will know.

[AudricV]

A Peertube test is failing because of a new thumbnail URL, which changes at every time the test is run.