This PR is fixing the Task/Note Target picker.
## Issue
A few weeks ago, we have simplified the recordPicker logic. During this
refacto, we stopped making sure the selected records were fetched.
However, the optimistic update of the activity supposed that current
activityTargets are present in the selection in the picker in order to
filter out the removed items.
## Fix
In case we don't find the record in the picker selection, we don't
filter it out (it means the user cannot have removed it)
## Next step
@ijreilly I think we should put it back, as the selected records do not
appear on top anymore
69f052e3ad