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.go

@@ -133,7 +133,6 @@ type InstanceSetup struct {
 type InstanceSetupFeatures struct {
 	LoginDefaultOrg                *bool
 	UserSchema                     *bool
-	TokenExchange                  *bool
 	ImprovedPerformance            []feature.ImprovedPerformanceType
 	DebugOIDCParentError           *bool
 	OIDCSingleV1SessionTermination *bool
@@ -167,7 +166,6 @@ func (f *InstanceSetupFeatures) ToInstanceFeatures() (_ *InstanceFeatures, err e
 	return &InstanceFeatures{
 		LoginDefaultOrg:                f.LoginDefaultOrg,
 		UserSchema:                     f.UserSchema,
-		TokenExchange:                  f.TokenExchange,
 		ImprovedPerformance:            f.ImprovedPerformance,
 		DebugOIDCParentError:           f.DebugOIDCParentError,
 		OIDCSingleV1SessionTermination: f.OIDCSingleV1SessionTermination,