fix(dev): Patch firefox_profile.py from Selenium package (#29887)

Running `pytest` in `getsentry` triggers a bug in `firefox_profile.py` from the Selenium driver. Upgrading to version 4 is quite involved. This is a stop-gap to prevent distracting engineers when it happens.

requirements-base.txt

@@ -89,5 +89,5 @@ phabricator==0.7.0
 
 # test dependencies, but unable to move to requirements-test until
 # sentry.utils.pytest and sentry.testutils are moved to tests/
-selenium==3.141.0
+selenium==3.141.0  # When upgrading, remove hack from lib.sh (see https://github.com/getsentry/sentry/pull/29887 for details)
 sqlparse==0.2.4

scripts/lib.sh

@@ -119,6 +119,13 @@ install-py-dev() {
         # https://github.com/unbit/uwsgi/issues/2361
         pip install https://storage.googleapis.com/python-arm64-wheels/uWSGI-2.0.19.1-cp38-cp38-macosx_11_0_universal2.whl
     fi
+    # This hack is until we can upgrade to a newer version of Selenium
+    fx_profile=.venv/lib/python3.8/site-packages/selenium/webdriver/firefox/firefox_profile.py
+    # Remove this block when upgrading the selenium package
+    if grep -q "or setting is" "${fx_profile}"; then
+        echo "We are patching ${fx_profile}. You will see this message only once."
+        patch -p0 <scripts/patches/firefox_profile.diff
+    fi
     # SENTRY_LIGHT_BUILD=1 disables webpacking during setup.py.
     # Webpacked assets are only necessary for devserver (which does it lazily anyways)
     # and acceptance tests, which webpack automatically if run.

scripts/patches/firefox_profile.diff

@@ -0,0 +1,7 @@
+--- .venv/lib/python3.8/site-packages/selenium/webdriver/firefox/firefox_profile.py	2021-11-09 16:40:20.000000000 -0500
++++ .venv/lib/python3.8/site-packages/selenium/webdriver/firefox/firefox_profile.py.bak	2021-11-09 16:40:03.000000000 -0500
+@@ -207,3 +207,3 @@
+     def _set_manual_proxy_preference(self, key, setting):
+-        if setting is None or setting is '':
++        if setting is None or setting == '':
+             return