cerbero: Fix bundle-source command

It was missing an --offline flag, to match build and package.
7 jobs for fix-bundlesource in 64 minutes and 23 seconds
Status Job ID Name Coverage
  Preparation
passed #85792
manifest

00:00:41

 
  Build
passed #85793
cerbero deps fedora x86_64

00:47:52

passed #85794
cerbero deps windows x86

00:45:09

passed #85795
cerbero deps windows x86_64

00:45:39

 
  Full Builds
passed #85797
build cerbero cross win32

00:15:49

passed #85798
build cerbero cross win64

00:12:41

passed #85796
build cerbero fedora x86_64

00:13:22