pf: fix 'no rdr'

Ensure we always have a non-NULL rule pointer (ctx.rm).
It might have gotten set to NULL by pf_get_translation().

While here also restore the previous rdr behaviour be re-adding the incorrectly
removed 'break' in pf_match_translation_rule.

PR: 290177
MFC after: 3 days
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D53191