[CBBS] Scheduled merges with offsets always fail

Problem

Planned merges with offsets do not work. Before a planned merge with merge options (i.e. offsets) runs, we run "cbbackupmgr info" to check if backups exist, using the date ranges we get from the range job. Prior to MB-58028, we passed a short date range, in the format DD-MM-YYYY e.g. 13-03-2024,14-03-2024. The date range passed to the job was changed in MB-58028 to the RFC3339Nano format i.e. 13-03-202400:00:00Z,14-03-202423:59:59.999999999Z. These date ranges are eventually passed to cbbackupmgr info via the --start and --end flags. When using a longer date format, cbbackupmgr info checks to see if a backup exists with that exact time. Since it is very unlikely that a backup exists with that name, the info command will fail, meaning that the merge will never run, regardless of how many days the plan has been running.

Release Plan

We have decided we will document this as a known issue in the Trinity release notes and fix it subsequently.

Release notes: Scheduled merges - that is merges which are done due to a task in a plan - will always fail. The merge will not be done and the backups that should have been merged will be left in place so no data is lost, and it will be as if there no merge was attempted. Manual merges can be done through the UI or using the API.

Fix

Potential fIxes:

1. Change the format of the date range back to the old, shorter one
2. Revert MB-60273 and MB-58028 (but then the timezone issue that caused CBSE-14809 would still be present) CHOSEN
3. Change cbbackupmgr info to never check for existing backups, even with a long date time.