Add a confirmation dialog for excessivly large downloads.

[H3wastooshort]

Problem:
Sometimes Jellyfin does a silly and groups >2000 random songs into one album. This can lead to unexpected storage useage. I wanted to download an entire Artist with just a few songs but instead filled my storage with thousands of random songs (I did not even know I hoarded that much over the years heh).
I deleted that artist download and wen from >6000 downloads to ~900.

suggested solution:
Add a confirmation dialog along the lines of "Do you really want to download 9999 Songs?"