Change PR deployment to build artifact + deploy

[nguyentvan7]

Describe your changes

• Changes described below should allow forks to have proper deployments while also deploying from a correct merge commit, unlike previous deployment implementations.
• Change PR deployment to use artifact-based system
• Build pipelines are triggered on PRs using pull_request event
  • This event has no secret access for forks, and requires contributor approval based on the repo settings.
  • This event will also wait to trigger until the mergeability check is complete and there is a merge commit available.
• Once the build is complete, it will archive the output.
• The completion of the build pipeline will trigger a separate deployment pipeline (this will not be shown in the Checks of a PR)
• Deployment pipeline runs from our master branch, and has full secret permissions.
• Deployment pipeline will download the artifact, push the contents to our deployment repo, and spawn/edit a comment on the original PR
• Moved the clean pipeline to use pull_request_target.
  • This event has secret access for forks, and does not require approval.
  • This event always runs the workflow contents from master branch, so a developer cannot hijack our pipeline.
  • This event will trigger before the mergeability check is complete.
  • This isn't an issue because we don't need the merge commit for this to run, we just need secret permissions.

Issue or discord link

• Resolves Convert PR deployment pipeline to be a build -> upload drop -> deploy pipeline #1575

Testing/validation

Tested on my own repo nguyentvan7#27
Deployment succeeded, comment appeared as expected. We won't be able to test the fork-based capabilities until this is merged into the main repo. But at the very least, it is not a regression for non-fork branches.

Checklist before requesting a review (leave this PR as draft if any part of this list is not done.)

• I have commented my code in hard-to understand areas.
• I have made corresponding changes to README or wiki.
• For front-end changes, I have updated the corresponding English translations.
• I have run yarn run mini-ci locally to validate format and lint.
• If I have added a new library or app, I have updated the deployment scripts to ignore changes as needed

[frzyc]

LGTM, looks like it works on your own repo as well. One minor nit.