Update current_milestone logic

Attempted to address issue reported in gitlab-org/quality/triage-reports#9321 (comment 1140104938) but ended up finding another improvement that needs to be made for correctly parsing the current milestone.

There is a bug with the reported issue not properly grouping the flags, I suspect that flags is not intended to be used to create issues, but instead we want flags_by_group[group]. Let me know if this is the correct fix It's not the right fix. so we need to do more digging.