[9.20] fix: usr: Valid TSIG signatures with invalid time cause crash
requested to merge backport-4811-fix-isc_buffer_putuint48-buffer-size-requirement-9.20 into bind-9.20
An assertion failure triggers when the TSIG has valid cryptographic signature, but the time is invalid. This can happen when the times between the primary and secondary servers are not synchronised.
Closes #4811 (closed)
Backport of MR !9234 (merged)