[9.20] fix: test: Bump edns-expire refresh timeout to 30 seconds

Rarely, RNDC fails to refresh the zone on FreeBSD in the default 10
seconds, causing test_edns_expire_refresh to fail with a TimeoutExpired
on the "rndc refresh edns-expire." call.  Give it more time, the same
way the reconfigure timeout was bumped in
test_reconfiguration_when_zone_transfer_is_in_the_middle_of_soa_query.

Assisted-by: Claude:claude-opus-4-8
Backport of MR !12152

Merge branch 'backport-mnowak/bump-edns-expire-refresh-rndc-timeout-9.20' into 'bind-9.20'

See merge request isc-projects/bind9!12153