Improve SongDetails retrieval logic

[kinsi55]

Reuse the same instance after having created one so you dont need to double send data after the first init

Might contain some minor syntax issues, I edited with the GH web editor but logic should be fine

[ReadieFur]

Updated in commit 2.0.10...2.0.11

[kinsi55]

With how you changed the beatSaver.BeatmapByHash(mapHash) call, its on the main thread. This is fine for the SongDetails load because it itself uses a Task.Run() internally but I'm not too sure if BeatmapByHash does that

[ReadieFur]

Interesting, though I don't believe this will be a problem as the data it sets and checks is minimal and shouldn't impact much, though I don't know about the function I'm waiting on itself, how that could affect things. From my quick tests it still seemed fine.