chore(oidc): remove feature flag for introspection triggers (#10132)

# Which Problems Are Solved

Remove the feature flag that allowed triggers in introspection. This
option was a fallback in case introspection would not function properly
without triggers. The API documentation asked for anyone using this flag
to raise an issue. No such issue was received, hence we concluded it is
safe to remove it.

# How the Problems Are Solved

- Remove flags from the system and instance level feature APIs.
- Remove trigger functions that are no longer used
- Adjust tests that used the flag.

# Additional Changes

- none

# Additional Context

- Closes #10026 
- Flag was introduced in #7356

---------

Co-authored-by: Silvan <27845747+adlerhurst@users.noreply.github.com>

console/src/assets/i18n/en.json

@@ -1629,8 +1629,6 @@
       "LOGINDEFAULTORG_DESCRIPTION": "The login UI will use the settings of the default org (and not from the instance) if no organization context is set",
       "OIDCTOKENEXCHANGE": "OIDC Token Exchange",
       "OIDCTOKENEXCHANGE_DESCRIPTION": "Enable the experimental urn:ietf:params:oauth:grant-type:token-exchange grant type for the OIDC token endpoint. Token exchange can be used to request tokens with a lesser scope or impersonate other users. See the security policy to allow impersonation on an instance.",
-      "OIDCTRIGGERINTROSPECTIONPROJECTIONS": "OIDC Trigger introspection Projections",
-      "OIDCTRIGGERINTROSPECTIONPROJECTIONS_DESCRIPTION": "Enable projection triggers during an introspection request. This can act as workaround if there are noticeable consistency issues in the introspection response but can have an impact on performance. We are planning to remove triggers for introspection requests in the future.",
       "USERSCHEMA": "User Schema",
       "USERSCHEMA_DESCRIPTION": "User Schemas allow to manage data schemas of user. If the flag is enabled, you'll be able to use the new API and its features.",
       "ACTIONS": "Actions",