fix: usr: Fix caching RRSIG covering cache NODATA record

When a RRSIG for type that we already have cached NODATA record was cached due to mismatch of the records on the upstream nameservers, an assertion failure could trigger.  This has been fixed.

Closes #5633

Merge branch '5633-evict-related-rrsig-when-adding-negative-header' into 'main'

See merge request isc-projects/bind9!11228