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)

internal/query/instance_features_model.go

@@ -67,7 +67,6 @@ func (m *InstanceFeaturesReadModel) Query() *eventstore.SearchQueryBuilder {
 			feature_v2.InstanceLegacyIntrospectionEventType,
 			feature_v2.InstanceUserSchemaEventType,
 			feature_v2.InstanceTokenExchangeEventType,
-			feature_v2.InstanceActionsEventType,
 			feature_v2.InstanceImprovedPerformanceEventType,
 			feature_v2.InstanceWebKeyEventType,
 			feature_v2.InstanceDebugOIDCParentErrorEventType,
@@ -98,7 +97,6 @@ func (m *InstanceFeaturesReadModel) populateFromSystem() bool {
 	m.instance.LegacyIntrospection = m.system.LegacyIntrospection
 	m.instance.UserSchema = m.system.UserSchema
 	m.instance.TokenExchange = m.system.TokenExchange
-	m.instance.Actions = m.system.Actions
 	m.instance.ImprovedPerformance = m.system.ImprovedPerformance
 	m.instance.OIDCSingleV1SessionTermination = m.system.OIDCSingleV1SessionTermination
 	m.instance.DisableUserTokenEvent = m.system.DisableUserTokenEvent
@@ -113,7 +111,8 @@ func reduceInstanceFeatureSet[T any](features *InstanceFeatures, event *feature_
 		return err
 	}
 	switch key {
-	case feature.KeyUnspecified:
+	case feature.KeyUnspecified,
+		feature.KeyActionsDeprecated:
 		return nil
 	case feature.KeyLoginDefaultOrg:
 		features.LoginDefaultOrg.set(level, event.Value)
@@ -125,8 +124,6 @@ func reduceInstanceFeatureSet[T any](features *InstanceFeatures, event *feature_
 		features.UserSchema.set(level, event.Value)
 	case feature.KeyTokenExchange:
 		features.TokenExchange.set(level, event.Value)
-	case feature.KeyActions:
-		features.Actions.set(level, event.Value)
 	case feature.KeyImprovedPerformance:
 		features.ImprovedPerformance.set(level, event.Value)
 	case feature.KeyWebKey: