Remove python installation from downstream-builder

[rileykarson]

This doesn't appear to be in use anymore- this cuts down our image build time substantially taking 600s (10m) on my machine, versus around 25m before.

One or both of LC_ALL and LANG are load bearing and I'm not entirely sure why. I got an encoding error without them when I got to bigqueryconnection or bigquerydatapolicy in MMv1 when running inside the image.

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Generated Terraform providers, and ran make test and make lint in the generated providers to ensure it passes unit and linter tests.
• Ran relevant acceptance tests using my own Google Cloud project and credentials (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

[rileykarson]

Running locally with docker run -it --entrypoint /bin/bash gcr.io/graphite-docker-images/downstream-builder:rileykarson and some setup:

root@bc4fa81fe0fd:/go/magic-modules# make provider VERSION=ga OUTPUT_PATH=/go/terraform-provider-google
<snip>
root@bc4fa81fe0fd:/go/magic-modules# echo $?
0

[slevenick]

There are probably more instances we can remove like https://github.com/GoogleCloudPlatform/magic-modules/blob/main/mmv1/compile/core.rb#L225

But those can come later