call-window: inhibit idle during active call

Closes #202
8 jobs for master in 12 minutes and 47 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #316233
librem5
build:native

00:02:14

 
  Test
passed #316235
librem5
build-gtkdoc

00:02:16

passed #316236
librem5
check-po

00:00:24

passed #316234
librem5
test:native

00:02:08

 
  Package
passed #316237
librem5
package:deb-debian-buster

00:02:10

passed #316238
librem5:arm64
package:deb-debian-buster:arm64

00:06:57

 
  Test Package
passed #316239
librem5
autopkgtest-debian-buster-package

00:01:17

passed #316240
librem5
lintian-debian-buster-package

00:00:31