KEYCLOAK-1822 Don't redirect to login theme when error during link identity in account mgmt.

forms/common-themes/src/main/resources/theme/base/account/messages/messages_en.properties

@@ -133,6 +133,7 @@ federatedIdentityLinkNotActiveMessage=This identity is not active anymore.
 federatedIdentityRemovingLastProviderMessage=You can''t remove last federated identity as you don''t have password.
 identityProviderRedirectErrorMessage=Failed to redirect to identity provider.
 identityProviderRemovedMessage=Identity provider removed successfully.
+identityProviderAlreadyLinkedMessage=Federated identity returned by {0} is already linked to another user.
 
 accountDisabledMessage=Account is disabled, contact admin.
 

forms/common-themes/src/main/resources/theme/base/login/messages/messages_en.properties

@@ -185,7 +185,6 @@ resetCredentialNotAllowedMessage=Reset Credential not allowed
 
 permissionNotApprovedMessage=Permission not approved.
 noRelayStateInResponseMessage=No relay state in response from identity provider.
-identityProviderAlreadyLinkedMessage=The identity returned by the identity provider is already linked to another user.
 insufficientPermissionMessage=Insufficient permissions to link identities.
 couldNotProceedWithAuthenticationRequestMessage=Could not proceed with authentication request to identity provider.
 couldNotObtainTokenMessage=Could not obtain token from identity provider.