Omit input group from ingestion manifest if it's empty

apps/cli/executables/pexable/ingest_envoy/ingest_envoy/ingestion_manifest.py

@@ -178,10 +178,15 @@ class IngestionManifest(ManifestComponentIF):
 
         to_return = {
             IngestionManifestKey.PARAMETERS.value: self.parameters.to_json(),
-            IngestionManifestKey.INPUT_GROUP.value: me_dict[IngestionManifestKey.INPUT_GROUP.value].to_json(),
             IngestionManifestKey.OUTPUT_GROUP.value: me_dict[IngestionManifestKey.OUTPUT_GROUP.value].to_json(),
         }
 
+        # Ingestion manifests with empty input groups can cause errors on ingest
+        if me_dict[IngestionManifestKey.INPUT_GROUP.value]:
+            to_return[IngestionManifestKey.INPUT_GROUP.value] = me_dict[
+                IngestionManifestKey.INPUT_GROUP.value
+            ].to_json()
+
         return to_return