Draft: Resolve all todos when user submits an MR review

What does this MR do and why?

We changed todo resolution in %17.2 to resolve todos one discussion at a time. This negatively impacted the flow for submitting code reviews though, as those primarily behave as discussion notes internally. This MR restores the previous behavior: when submitting a review, all of the current user's todos for the MR are resolved.

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