fix: Add async context manager return types (#440)

* fix: Add async context manager return types

chore: Mock return_value should not populate oneof message fields

chore: Support snippet generation for services that only support REST transport

chore: Update gapic-generator-python to v1.11.0
PiperOrigin-RevId: 545430278

Source-Link: googleapis/googleapis@601b532

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google/cloud/language_v1/services/language_service/async_client.py

@@ -1019,7 +1019,7 @@ async def sample_annotate_text():
         # Done; return the response.
         return response
 
-    async def __aenter__(self):
+    async def __aenter__(self) -> "LanguageServiceAsyncClient":
         return self
 
     async def __aexit__(self, exc_type, exc, tb):

google/cloud/language_v1beta2/services/language_service/async_client.py

@@ -1020,7 +1020,7 @@ async def sample_annotate_text():
         # Done; return the response.
         return response
 
-    async def __aenter__(self):
+    async def __aenter__(self) -> "LanguageServiceAsyncClient":
         return self
 
     async def __aexit__(self, exc_type, exc, tb):

samples/generated_samples/snippet_metadata_google.cloud.language.v1.json

@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-language",
-    "version": "2.10.0"
+    "version": "0.1.0"
   },
   "snippets": [
     {

samples/generated_samples/snippet_metadata_google.cloud.language.v1beta2.json

@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-language",
-    "version": "2.10.0"
+    "version": "0.1.0"
   },
   "snippets": [
     {