Maintenance window now scheduled weekly on Tuesdays

[getvictor]

#19031

• Maintenance window now scheduled weekly on Tuesdays

Checklist for submitter

If some of the following don't apply, delete the relevant line.

• [x] Changes file added for user-visible changes in changes/, orbit/changes/ or ee/fleetd-chrome/changes. See Changes files for more information.
• [x] Added/updated tests
• [x] Manual QA for all new/changed functionality