Slow library loading with more entries in exclusion list

[Andrius-B]

Shuttle version:

Can be observed in 2.0.17 but also in commit b4cd6f0286db3eb9cdea8338e54d7081af0618e1

Description of bug:

The library takes a very long time to load on a cold start, when the blacklist has a moderate amount of entries (~860 in this case).
This evening I compiled the dev branch to see if the problem is fixed, but it seems the problem still persists.
To do more measurements, I added a couple of log messages to the AlbumListPresenter.kt, where the albums are fetched and here are the times for album load without blacklisting and then with blacklisting:

[(no exclusions) + app start..]
2021-08-24 20:18:58.499 838-838/com.simplecity.amp_pro.debug I/PERF: Requested album load
2021-08-24 20:18:59.101 838-1194/com.simplecity.amp_pro.debug I/PERF: 295 albums loaded in 602ms
[app restart..]
2021-08-24 20:20:01.638 2539-2539/com.simplecity.amp_pro.debug I/PERF: Requested album load
2021-08-24 20:20:02.177 2539-2699/com.simplecity.amp_pro.debug I/PERF: 295 albums loaded in 539ms
[blacklist spotify cache folders + app restart..]
2021-08-24 20:20:48.613 2956-2956/com.simplecity.amp_pro.debug I/PERF: Requested album load
2021-08-24 20:20:59.795 2956-3028/com.simplecity.amp_pro.debug I/PERF: 188 albums loaded  in 11182ms
[app restart..]
2021-08-24 20:21:24.084 3357-3357/com.simplecity.amp_pro.debug I/PERF: Requested album load
2021-08-24 20:21:35.167 3357-3434/com.simplecity.amp_pro.debug I/PERF: 188 albums loaded in 11082ms

These are measured with System.nanoTime(), but the lag is very noticeable - blank screen for around 10 seconds.