"Force read-only" setting not effective immediately

[rfc2822]

Problem scope

• I'm sure that this is a DAVx⁵ problem.

App version

• I'm using the latest available DAVx⁵ version.

Android version and device/firmware type

No response

Steps to reproduce

The "Force read-only" setting of collections (Contacts, calendars, ..) only becomes effective after another sync.

Steps to reproduce:

1. Open ie Contacts tab
2. Check "Force read-only" on a collection, that was just enabled
3. Change to Contacts app -> You can still edit the contact

Issuing a sync in davx5 will make the change effective. Same goes for unchecking the collection.

Actual result

No response

Expected result

No response

Further info

See https://github.com/bitfireAT/davx5/issues/151; maybe we can just find and update the LocalCollection immediately.