flatpak: Add mozjs52

It is required by polkit.
11 jobs for flatpak in 4 minutes and 1 second (queued for 3 minutes and 5 seconds)
Status Job ID Name Coverage
  Build
passed #104185
build

00:01:45

 
  Test
passed #104187
asan

00:01:37

passed #104186
test

00:00:38

 
  Manual
manual #104192
allowed to fail manual
armv8
manual #104188
allowed to fail manual
flatpak
manual #104191
allowed to fail manual
msan
manual #104193
allowed to fail manual
ppc64le
manual #104189
allowed to fail manual
tsan
manual #104190
allowed to fail manual
ubsan
 
  Review
manual #104194
allowed to fail manual
review
manual #104195
allowed to fail manual
stop_review