api: Add observability controller to router

Allow endpoint controller methods to be recognized, as well as generate
call scripts for local testing via contrib/ scripts.

BUG=b:224589938
TEST=./gen_call_scripts produces callable for ObservabilityService

Change-Id: I32ab0484e31eeb08adb599b19d0463a56f324a1b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3699202
Commit-Queue: Lizzy Presland <zland@google.com>
Tested-by: Lizzy Presland <zland@google.com>
Reviewed-by: Alex Klein <saklein@chromium.org>
diff --git a/api/router.py b/api/router.py
index c8df8d4..70bfc0e 100644
--- a/api/router.py
+++ b/api/router.py
@@ -28,6 +28,7 @@
 from chromite.api.gen.chromite.api import firmware_pb2
 from chromite.api.gen.chromite.api import image_pb2
 from chromite.api.gen.chromite.api import metadata_pb2
+from chromite.api.gen.chromite.api import observability_pb2
 from chromite.api.gen.chromite.api import packages_pb2
 from chromite.api.gen.chromite.api import payload_pb2
 from chromite.api.gen.chromite.api import portage_explorer_pb2
@@ -484,6 +485,7 @@
     router.Register(firmware_pb2)
     router.Register(image_pb2)
     router.Register(metadata_pb2)
+    router.Register(observability_pb2)
     router.Register(packages_pb2)
     router.Register(payload_pb2)
     router.Register(portage_explorer_pb2)