Revert "service: Raise exception when payload generation is skipped"

This reverts commit 9cb38d43abeaa1aadd07ece4034879ea72324c29.

Reason for revert: b/241565562#comment19

Original change's description:
> service: Raise exception when payload generation is skipped
>
> Continuation of crrev.com/3856784 where Rubik handlers need exception
> raised to skip upload check.
>
> BUG=b:243792598
> TEST=./run_tests -- -x service
>
> Change-Id: I5e5d7ad925cf0ae708dd261248419f3c02209dcc
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3857493
> Commit-Queue: Jae Hoon Kim <kimjae@chromium.org>
> Commit-Queue: George Engelbrecht <engeg@google.com>
> Tested-by: George Engelbrecht <engeg@google.com>
> Tested-by: Jae Hoon Kim <kimjae@chromium.org>
> Reviewed-by: George Engelbrecht <engeg@google.com>
> Auto-Submit: Jae Hoon Kim <kimjae@chromium.org>

Bug: b:243792598
Change-Id: I0a353622cfc31ce4ba94bf5b0baf61f002d7cf5a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3858034
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Tested-by: George Engelbrecht <engeg@google.com>
Auto-Submit: Jae Hoon Kim <kimjae@chromium.org>
Reviewed-by: George Engelbrecht <engeg@google.com>
diff --git a/api/controller/payload.py b/api/controller/payload.py
index 600f8de..dc11e0c 100644
--- a/api/controller/payload.py
+++ b/api/controller/payload.py
@@ -100,11 +100,11 @@
   local_path, remote_uri = '', ''
   try:
     local_path, remote_uri = payload_config.GeneratePayload()
-  except paygen_payload_lib.PayloadGenerationSkippedException:
+  except paygen_payload_lib.PayloadGenerationSkippedException as e:
     # If paygen was skipped, provide a reason if possible.
-    # Only reason to skip right now is missing miniOS partitions.
-    reason = payload_pb2.GenerationResponse.NOT_MINIOS_COMPATIBLE
-    output_proto.failure_reason = reason
+    if isinstance(e, paygen_payload_lib.NoMiniOSPartitionException):
+      reason = payload_pb2.GenerationResponse.NOT_MINIOS_COMPATIBLE
+      output_proto.failure_reason = reason
 
   _SetGeneratePayloadOutputProto(output_proto, local_path, remote_uri)
   if remote_uri or input_proto.dryrun and local_path: