window: Show MUC chats with empty messages

All active MUC chats should be shown even when
the chat contain no messages

Fixes #377
8 jobs for wip/sadiq/always-show-muc in 13 minutes and 8 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Build
passed #306572
librem5
build-debian-gcc-bullseye

00:03:23

passed #306571
librem5
build-debian-gcc-buster

00:02:32

 
  Test
passed #306574
librem5
check-po

00:00:25

passed #306573
librem5
test:debian-gcc

00:02:11

21.1%
 
  Package
passed #306575
librem5
package:deb-debian-buster

00:01:43

passed #306576
librem5:arm64
package:deb-debian-buster:arm64

00:06:22

 
  Test Package
passed #306577
librem5
autopkgtest-debian-buster-package

00:01:09

passed #306578
librem5
lintian-debian-buster-package

00:00:31