opening two configuration dolphins blocks a close event from triggering

[NikhilNarayana]

I noticed a very weird interaction where if you open two dolphins for configuring, the close event of the dolphin opened second won't trigger until you close the dolphin you opened first. This doesn't happen when you launch netplay and a replay.

Steps to repro:

1. Add some log statements in the close events for configuration dolphins.
2. Configure a Netplay Dolphin.
3. Configure a Playback Dolphin.
4. Close Playback Dolphin, notice that the log message doesn't show up.
5. Close Netplay dolphin, notice that the log message for netplay shows up immediately and then the log message for playback shows up.

[FluentCoding]

I looked into this issue and it apparently seems like the main thread of the playback dolphin build doesn't end even if you close the application, so I suppose that this issue has nothing to do with the slippi launcher itself. (see the lower task of the image which is the result of following every step up to step 4)