fix: usr: Fix DNS-over-HTTPS (DoH) quota configuration issue

The :any:`http-listener-clients` and :any:`http-streams-per-connection`
configuration options could be truncated to smaller values (or to ``0``,
which means unlimited) when very big configuration values were used, which
exceeded ``65535``. As a note - it is very unlikely that such big values
are used in production, and the default values for the affected options
are ``300`` and ``100``, correspondingly. This has been fixed.

Closes #6021

Merge branch '6021-doh-quota-type-truncation-fix' into 'main'

See merge request isc-projects/bind9!12085