feat(workspace): Add subdomain availability check (#8906)

Implemented a feature to check the availability of subdomains when
updating workspace settings. This includes a new mutation,
`isSubdomainAvailable`, to validate subdomain availability through
GraphQL. The frontend now verifies if a subdomain is available to
prevent duplicates during updates.

---------

Co-authored-by: Weiko <corentin@twenty.com>

packages/twenty-front/src/modules/workspace/components/WorkspaceProviderEffect.tsx

@@ -41,8 +41,10 @@ export const WorkspaceProviderEffect = () => {
   useEffect(() => {
     if (
       isMultiWorkspaceEnabled &&
-      isDefined(lastAuthenticatedWorkspaceDomain?.subdomain) &&
-      isDefaultDomain
+      isDefaultDomain &&
+      isDefined(lastAuthenticatedWorkspaceDomain) &&
+      'subdomain' in lastAuthenticatedWorkspaceDomain &&
+      isDefined(lastAuthenticatedWorkspaceDomain?.subdomain)
     ) {
       redirectToWorkspaceDomain(lastAuthenticatedWorkspaceDomain.subdomain);
     }