Broken scheduled notices are blocking notice delivery

Overview:
Steps to Reproduce:

1. Log into some FOLIO environment as User X
2. Generate scheduled notices
3. Delete a patron group of some of the patrons notices are scheduled for

Expected Results:

"broken" notices (with missing patron group) shouldn't stop others from being delivered
Actual Results:

"broken" notices stop others from being delivered
Additional Information:
It was discovered by FSE team (sduvvuri ) during the investigation of NPE issue (CIRC-1286). If CIRC-1286 is closed first and NPE is no longer reproducible, this ticked should be treated as a tech debt to make sure "broken" scheduled notices don't block notice delivery.
Interested parties: