xep-0313: use default archive preference from server

The user message archiving default retrieved from the server should be
maintained and not overridden.
7 jobs for mam_pref_fix in 8 minutes and 16 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed build-pureos-gcc-byzantium #367869
librem5

00:01:44

 
  Test
passed check-po #367871
librem5

00:00:36

passed test:debian-gcc #367870
librem5

00:01:32

21.6%
 
  Package
passed package-pureos-byzantium #367872
librem5

00:01:39

passed package-pureos-byzantium:arm64 #367873
librem5:arm64

00:04:58

 
  Test Package
passed autopkgtest-pureos-byzantium-package #367874
librem5

00:01:19

passed lintian-pureos-byzantium-package #367875
librem5

00:00:36