Fixes part of #11462: Update install_backend_python_libs to respect direct urls from GitHub

[brianrodri]

Overview

1. This PR fixes or fixes part of Migrate from GAE user authentication to Firebase authentication #11462.
2. This PR does the following: Currently we skip Git requirements, but that has proven to be unhelpful since it's important that very specific commits are installed. This PR updates the logic to require that a specific commit is installed, and re-installs when that's not the case.

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Proof that changes are correct

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[oppiabot]

Assigning @DubeySandeep for the first-pass review of this pull request. Thanks!

[vojtechjelinek]

LGTM!

[nithusha21]

LGTM for my codeowner files!

[oppiabot]

Unassigning @nithusha21 since they have already approved the PR.

[aks681]

Lgtm as codeowner

[oppiabot]

Hi @brianrodri, the build of this PR is stale and this could result in tests failing in develop. Please update this pull request with the latest changes from develop. Thanks!

[DubeySandeep]

LGTM for the coedeowner files.

[DubeySandeep]

Hi @brianrodri It looks like this PR is creating an issue for developers while pushing the changes, see #12362 for more info!

I'm initiating a revert PR for now, if you can create a PR to fix the issue quickly then we can merge that instead of revert!