Python test handler visually resolved prematurely

[Yoyokrazy]

Testing #21306

changed test_subtests.py to range (0, 10k), all visual indicators resolve before output is updated.

edit: was previously testing with range (0, 1mil) which could have bled over -- causing the weirder outputs and issues.

Python output logs continue to print 2023-05-30 14:55:57.210 [info] On data received: Error occurred because the payload UUID is not recognized

[eleanorjboyd]

behavior appears to be different when running on a test class vs the workspace, this should be investigated further.

[eleanorjboyd]

another related issue- the tests in the test output bottom panel didn't end up resolving even though the text explorer UI did and all the tests ran. This occurred when 100k subtests were run so it could be a load issue.

[eleanorjboyd]

should be fixed by #21351 as well. Just checked and was not able to repro the behavior anymore.