When requests are made to the webhook_subscription there is one method that when called is disposing of the github client. In the _checkForTests methods it calls dispose on the github client which closes the connection while it is still in scope. This is the only part of the code that does this. This was killing the client for any pull request event for edited, opened, and reopened but not synchronized.

The fix will be investigated further but this prevents .ci.yaml checks and other issues blocking checkRuns from starting.

List which issues are fixed by this PR. You must list at least one issue.
Fixes: flutter/flutter#129134

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• I listed at least one issue that this PR fixes in the description above.
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