Consider removing pact from requirements

[kdmccormick]

pact is currently the platform's single largest dev depenedency, taking ~30s to install into the dev image:

$ tutor dev run lms bash
app@04531af885b0:~/edx-platform$ cd /openedx/venv/lib/python3.8/site-packages
app@04531af885b0:~/venv/lib/python3.8/site-packages$ du -hs * | sort -h -r | head -n 10
145M	pact
101M	scipy
82M	snowflake
52M	sympy
48M	openassessment
45M	_sass.cpython-38-x86_64-linux-gnu.so
44M	django
35M	numpy.libs
34M	scipy.libs
34M	botocore

pact is a testing dependency of the platform, added by this PR: #28289

I believe only a handful of tests use pact:

~/openedx/edx-platform 🍀 find . -wholename */pacts/*
./common/test/pacts/__init__.py
./common/test/pacts/middleware.py
./openedx/core/djangoapps/courseware_api/tests/pacts/views.py
./openedx/core/djangoapps/courseware_api/tests/pacts/__init__.py
./openedx/core/djangoapps/courseware_api/tests/pacts/api-courseware-contract.json
./openedx/core/djangoapps/courseware_api/tests/pacts/verify_pact.py
./lms/djangoapps/courseware/tests/pacts/views.py
./lms/djangoapps/courseware/tests/pacts/__init__.py
./lms/djangoapps/courseware/tests/pacts/verify_pact.py
./lms/djangoapps/courseware/tests/pacts/course-xblock-handler-contract.json
./lms/djangoapps/course_api/blocks/tests/pacts/views.py
./lms/djangoapps/course_api/blocks/tests/pacts/__init__.py
./lms/djangoapps/course_api/blocks/tests/pacts/api-block-contract.json
./lms/djangoapps/course_api/blocks/tests/pacts/verify_pact.py

Questions

• What is the value of Pact, and it is worth 145M and extra build time for all devs?
• The PR, from 2021, refers to a "contact testing pilot". Is this still going?
• Are there plans to add more Pact tests?
• How hard would it be to migrate those test cases off of Pact?