TAStudio: Live recording activates at end of file

[SamsaraTAS]

Unpausing at the end of a file activates live-recording mode once new blank frames are added. This persists upon loading a branch. This only happens specifically when the movie is unpaused: Live-recording deactivates whenever frame advance is used, and frame-advancing past the end of the current file does not activate it.

Reproduction steps:

1. Create a new tasproj file and paint 100 frames of input
2. Set a branch at frame 1
3. Unpause the movie and let it run past frame 100
4. Pause the movie, load the branch, then unpause again

I think the intended behavior is that live-recording only activates whenever the movie is set to Read+Write, but this is happening with the movie set to Read-Only.

Thanks in advance for taking a look at this!