fix: dialog window should pop up to warn user of open compressor before SLTT-App starts

[AllisonPyle]

Actual: If a user tries to open SLTT-App on their computer when a compressor window is already open, it results in the following error:

Expected/Desired: If a user tries to open SLTT-App on their computer when a compressor window is already open, it should show them a clear error message to alert them to close the compressor window.

Eric suggested we could check for this and create a dialog that pops up in this scenario to give the user more clear information before the error appears.

See https://signlanguaget-nfl9249.slack.com/archives/C057S17G2L9/p1731016572054269

and https://signlanguaget-nfl9249.slack.com/archives/C057S17G2L9/p1731079960188309 .

To reproduce:

Open SLTT compressor and keep it open.

Open installed SLTT-App on same computer.

Error message pictured above should appear.