Email: trigger email verification flow (#85587)

* Add email and email_verified to id token if identity is a user

* Add endpoint to trigger email verification for user

* Add function to clear stored id tokens and use it when email verification is completed

pkg/services/authn/authnimpl/sync/user_sync.go

@@ -407,4 +407,5 @@ func syncSignedInUserToIdentity(usr *user.SignedInUser, identity *authn.Identity
 	identity.LastSeenAt = usr.LastSeenAt
 	identity.IsDisabled = usr.IsDisabled
 	identity.IsGrafanaAdmin = &usr.IsGrafanaAdmin
+	identity.EmailVerified = usr.EmailVerified
 }