fix: enable scenario termination from closing display

[abanuelo]

Description

Fix that allows users to manually close out display via the UI and continue subsequent simulations to continue. Here is a video illustrating the working changes

https://github.com/BerkeleyLearnVerify/Scenic/assets/32311654/a6b7d7e5-71b6-4580-b7a7-8b33d3e4da58

Issue Link

Checklist

• [X] I have tested the changes locally via pytest and/or other means
• [ ] I have added or updated relevant documentation
• [X] I have autoformatted the code with black and isort
• [ ] I have added test cases (if applicable)

Additional Notes

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.66667% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 85.96%. Comparing base (0232e6f) to head (bde9c32).

Files	Patch %	Lines
src/scenic/simulators/newtonian/simulator.py	60.00%	2 Missing :warning:
src/scenic/core/simulators.py	75.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #238 +/- ## ======================================= Coverage 85.96% 85.96% ======================================= Files 144 144 Lines 24768 24777 +9 ======================================= + Hits 21292 21300 +8 - Misses 3476 3477 +1 ```

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