Toast notification when download started

[illustribe]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• [ x] I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• [ x] This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

I think having a toast notification for when a download has started would be useful. Sometimes I wonder if I clicked correctly or just closed the download prompt without having it started, and then I have to go to downloads screen to double-check... That's it! :)

Is your feature request related to a problem? Please describe it

No

Additional context

How will you/everyone benefit from this feature?

I think toast notifications are quite widespread and standard and users maybe used to them or waiting for them...

[WoodyMats]

Hello! I'd like to work on this enhancement. Can i assigned to this issue? :)

[XiangRongLin]

@WoodyMats Go for it

[WoodyMats]

#5519 I made a pull request that contains code which has this enhancement. :)