Add self-hosted Sentry end-to-end tests to CI using new Github action

[emmatyping]

This is work as part of getsentry/self-hosted#1756

Essentially, we want to move from Google Cloudbuild to a centralized Github Action that can be used across Sentry/Snuba/Relay/self-hosted. This adds a job which should use that action.

[codecov-commenter]

Codecov Report

Base: 90.88% // Head: 90.89% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (71a33ba) compared to base (2da0f52).
Patch has no changes to coverable lines.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3401   +/-   ##
=======================================
  Coverage   90.88%   90.89%           
=======================================
  Files         711      712    +1     
  Lines       33130    33132    +2     
=======================================
+ Hits        30111    30114    +3     
+ Misses       3019     3018    -1     

Impacted Files	Coverage Δ
snuba/datasets/pluggable_entity.py	89.65% <0.00%> (ø)
snuba/datasets/storages/sessions.py	100.00% <0.00%> (ø)
snuba/datasets/configuration/utils.py	98.36% <0.00%> (ø)
snuba/datasets/configuration/json_schema.py	100.00% <0.00%> (ø)
tests/datasets/plans/test_partitioned_storage.py
snuba/datasets/plans/partitioned_storage.py
snuba/datasets/partitioning.py
snuba/datasets/plans/sliced_storage.py	74.07% <0.00%> (ø)
tests/datasets/plans/test_sliced_storage.py	100.00% <0.00%> (ø)
...processors/physical/minute_resolution_processor.py	100.00% <0.00%> (ø)
... and 2 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[hubertdeng123]

lgtm