Make cookie banner origin immutable after creation

Origin is a fundamental identity property of a banner tied to consent
records for a specific site. Changing it would break the audit trail
and violate GDPR consent specificity requirements.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/server/api/console/v1/graphql/cookie_banner.graphql

@@ -274,7 +274,6 @@ input CreateCookieBannerInput {
 input UpdateCookieBannerInput {
     cookieBannerId: ID!
     name: String
-    origin: String
     privacyPolicyUrl: String
     consentExpiryDays: Int
     consentMode: CookieConsentMode