fix: remove action feature flag and include execution (#9727)

# Which Problems Are Solved

Actions v2 is not a feature flag anymore, include functionality on
executions is not used and json tags of proto messages are handled
incorrectly.

# How the Problems Are Solved

- Remove actions from the feature flags on system and instance level
- Remove include type on executions, only in the API, later maybe in the
handling logic as well
- Use protojson in request and response handling of actions v2

# Additional Changes

- Correct integration tests for request and response handling
- Use json.RawMessage for events, so that the event payload is not
base64 encoded
- Added separate context for async webhook calls, that executions are
not cancelled when called async

# Additional Context

Related to #9759
Closes #9710

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>
(cherry picked from commit b8ba7bd5ba)

proto/buf.yaml

@@ -7,6 +7,10 @@ deps:
 breaking:
   use:
     - FILE
+    - FIELD_NO_DELETE_UNLESS_NAME_RESERVED
+    - FIELD_NO_DELETE_UNLESS_NUMBER_RESERVED
+  except:
+    - FIELD_NO_DELETE
   ignore_unstable_packages: true
 lint:
   use: