The stored rrule of a recurrence embeds a DTSTART line based on the recurrence dtstart (the smallest start among its events). When the first occurrence is moved in Outlook, the Odoo dtstart no longer matches that DTSTART, but the stored rrule is not recomputed at that point (it only depends on the pattern fields).

On a later sync touching the seriesMaster (e.g. after adding an attendee to the moved occurrence), the recurrence values are written again and the rrule is reserialized with a DTSTART based on the moved occurrence. _write_from_microsoft() took this new rrule string as a pattern change and reapplied the recurrence: all occurrences were deleted and recreated as copies of the moved one, spreading its specific data (e.g. the newly added attendee) to the whole series.

Ignore the DTSTART line when comparing the rrule before and after the write: a DTSTART-only difference does not reflect any pattern change in Outlook. An actual pattern change (FREQ, UNTIL, INTERVAL, ...) still reapplies the recurrence as before.

Steps to reproduce:
1. In Outlook, create a recurring event
2. In Odoo, run the calendar sync
3. In Outlook, move the first occurrence of the recurrence (shift its start and stop time by 30 minutes)
4. In Odoo, run the sync
5. In Outlook, add an attendee to that same first occurrence
6. In Odoo, run the sync

All the occurrences are deleted and recreated as copies of the first one, and the attendee ends up on every occurrence instead of one.

opw-5129848

Forward-Port-Of: odoo/odoo#284447
Forward-Port-Of: odoo/odoo#269549

Changing a project's visibility fails when its documents folder contains a shortcut.
The visibility change is never applied and the following error is raised:
"You can not update the access of a shortcut, update its target instead."

### Reproduction steps

- Create a project and add a document to its folder.
- Create another document outside the project's folder.
- Create a shortcut to that document in the project's folder.
- Change the project's visibility.

### Cause

Changing a project's visibility updates the access rights of its folder and documents together.

The shortcut access check is meant to reject operations performed only on shortcuts. However, reading `shortcut_document_id` on a recordset returns the shortcut targets found across that recordset. Therefore, the presence of a single shortcut makes the check reject the whole operation.

This prevents regular documents and the project folder from having their access updated.

### Fix

Only reject access updates when all records involved are shortcuts.

This preserves the protection against changing shortcut access directly while allowing project access updates to include shortcuts alongside regular documents and folders.

opw-6472637

Forward-Port-Of: odoo/enterprise#128756