Flutter Symbol Upload - Cron monitor

[bruno-garcia]

We recently got automated symbol collection for Flutter

• chore: flutter symbol collector CLI tool #1673

But currently there's no way to monitor it.

We can use Crons to monitor it. Similar to the Apple symbol upload:

https://github.com/getsentry/apple-system-symbols-upload/blob/f5a0da1fbe6639412714ecd0e1fd7be976d56e3b/.github/actions/import-system-symbols-from-ipsw/action.yml#L36

https://github.com/getsentry/apple-system-symbols-upload/blob/f5a0da1fbe6639412714ecd0e1fd7be976d56e3b/.github/workflows/import-system-symbols-from-ipsw-on-schedule.yml#L37