Revert Pandora process_monitor.py changes from 09ca4fa, 461cd58

[rtertiaer]

What does this change intend to accomplish?

This PR reverts the changes from 09ca4fa, 461cd58. We suspect these have caused stability concerns (#636, #663, and here.)

These changes have had seemingly limited utility, and Pandora worked well before. We stand to lose close to nothing reverting these changes.

I'm currently running this branch on an AmpliPi overnight and intend to ship it tomorrow if it works swell.

Checklist

• Have you tested your changes and ensured they work? (see above)
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• If applicable, have you updated the documentation/manual?
• If applicable, have you updated the CHANGELOG?
• Does your submission pass linting & tests? You can test on localhost using ./scripts/test
• Have you written new tests for your core features/changes, as applicable?

[linknum23]

I think this makes sense as a short term fix. We really need to characterize the failure/stop conditions of Pandora to rubustify this in the future.