pw_build: Lint & test deps in python_dist.gni templates
pw_build: Lint & test deps in python_dist.gni templates

The pw_create_python_source_tree and pw_internal_pip_install templates
can be used as python_deps, but their lint and test subtargets do
nothing instead of forwarding to their packages. This would make it easy
to accidentally stop linting and testing a bunch of packages.

Update these templates so their subtargets forward to a pw_python_group
of their packages.

Change-Id: I7f0e27bf4577a6779f310343ff3a8c21a86af2da
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/97443
Reviewed-by: Armando Montanez <97ef6fdb231c129ac8827d9f0c4106bfbf57f74f@google.com>
Pigweed-Auto-Submit: Wyatt Hepler <cca3bedb37979eacd157a9bceb473582df8aea1e@google.com>
Commit-Queue: Wyatt Hepler <cca3bedb37979eacd157a9bceb473582df8aea1e@google.com>

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed