d/librem5-ci: Drop check-tarball for the moment

Not needed for 3.0 (native)
4 jobs for fix-build in 2 minutes and 35 seconds (queued for 1 second)
Status Job ID Name Coverage
  Package
passed #346276
librem5
package-pureos-byzantium

00:00:48

passed #346277
librem5:arm64
package-pureos-byzantium:arm64

00:02:35

 
  Test Package
passed #346278
librem5
autopkgtest-pureos-byzantium-package

00:00:42

passed #346279
librem5
lintian-pureos-byzantium-package

00:00:38