feat(oauth/oidc): move token exchange from beta to GA (#11475)

# Which Problems Are Solved

This PR marks the OAuth2 Token Exchange as general available (GA).

# How the Problems Are Solved

- API:
- deprecated the feature toggle (to prevent breaking changes) in v2beta
and v2 API
- removed all related event logic and updated the projection interation
  - removed the toggle usage for token exchange
  - removed related translations
- Management Console:
  - removed the feature toggle and its translations
- Docs:
  - removed all beta labels and feature toggle notes

# Additional Changes

- removed unused `Errors.WebKey.FeatureDisabled` translations

# Additional Context

- closes #11114

---------

Co-authored-by: Marco A. <[email protected]>

internal/command/instance_features_model_test.go

@@ -38,15 +38,6 @@ func Test_reduceInstanceFeature(t *testing.T) {
 			},
 			expected: &InstanceFeatures{LoginDefaultOrg: gu.Ptr(true)},
 		},
-		{
-			name: "token exchange",
-			args: args{
-				features: &InstanceFeatures{},
-				key:      feature.KeyTokenExchange,
-				value:    true,
-			},
-			expected: &InstanceFeatures{TokenExchange: gu.Ptr(true)},
-		},
 		{
 			name: "user schema",
 			args: args{