Fix hang on model manager install unit tests

[lstein]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update
• Community Node Submission

Have you discussed this change with the InvokeAI team?

• Yes
• No, because:

Have you updated all relevant documentation?

• Yes
• No

Description

This PR fixes the periodic hang and timeout that occurs during the test_model_install and test_download unit tests. It also changes the default timeouts for unit tests (1 minute rather than 5 hours) and fixes the handling of the invokeai root during pytest.

Finally, it removes redundant and slow hashing calls executed during the model install process.

Related Tickets & Documents

See discord thread: https://discord.com/channels/1020123559063990373/1212521379593719918/1212521450393829417

• Related Issue #
• Closes #

QA Instructions, Screenshots, Recordings

Use git actions to run test_invoke.py pip repeatedly. There should no longer be intermittent hangs and timeouts.

Merge Plan

Merge after review.

Added/updated tests?

• Yes
• No : please replace this line with details on why tests
  have not been included

[optional] Are there any post deployment tasks we need to perform?

[psychedelicious]

I've rebased this on my rebased next branch, so we can merge that and get all tests passing on the rebased next branch.