feat(build_depends.repos): remove autoware_auto_msgs from build_depends.repos (#7252)

Signed-off-by: Ryohsuke Mitsudome <ryohsuke.mitsudome@tier4.jp>
Co-authored-by: Yukihiro Saito <yukky.saito@gmail.com>

Author: mitsudome-r

build_depends.repos

@@ -20,10 +20,6 @@ repositories:
     type: git
     url: https://github.com/autowarefoundation/autoware_internal_msgs.git
     version: main
-  core/external/autoware_auto_msgs:
-    type: git
-    url: https://github.com/tier4/autoware_auto_msgs.git
-    version: tier4/main
   # universe
   universe/external/tier4_autoware_msgs:
     type: git