Made it so dismissed approvals don't block the autosubmit bot.

[gaaclarke]

fixes flutter/flutter#185224

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[b-luk]

Also, not directly related to this change, but I notice that the UI lets me dismiss a REQUESTED_CHANGES review:

Does this mean that a REQUESTED_CHANGES review doesn't actually block an author from submitting, because they can always just dismiss that review? So REQUESTED_CHANGES is more of a suggestion than something that is enforceed?

Or is this UI something most people don't have, and I just see it because I have elevated permissions?

[gaaclarke]

Does this mean that a REQUESTED_CHANGES review doesn't actually block an author from submitting, because they can always just dismiss that review? So REQUESTED_CHANGES is more of a suggestion than something that is enforceed?

The requirement is that you have approval, not that there is no requests changes. Dismissing requests changes should be used respectfully obviously.

[b-luk]

This looks good to me, but I have no experience with this code or with how it works. So please also get approval from someone else who is more familiar with this.

[b-luk]

This is testing an impossible scenario, because our graphql query won't return a COMMENTED review. Maybe we can remove this test because it can be misleading.