UNAUTHORIZED gmail error (#12262)

# Gmail OAuth authentication flow issues

### TLDR
This error is not an error and therefore should be treated as a simple
redirect with a snackbar.

### More details
Fixing incomplete OAuth token exchange processes and improving error
handling for empty Gmail inboxes.
The changes include modifications to OAuth guards, to ensure that if a
user clicks "cancel" instead of completing the authentication workflow
if fails

## Before:
Redirection from `/settings/accounts` to `app.twenty.com` with an
`UNAUTHORIZED` error

## After :
<img width="948" alt="Screenshot 2025-05-26 at 18 04 37"
src="https://github.com/user-attachments/assets/62c8721e-c2b3-4e3d-ad0b-e4059dfb7a98"
/>


Fixes https://github.com/twentyhq/twenty/issues/11895

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

packages/twenty-server/src/engine/core-modules/domain-manager/services/domain-manager.service.ts

@@ -128,10 +128,11 @@ export class DomainManagerService {
   computeRedirectErrorUrl(
     errorMessage: string,
     workspace: WorkspaceSubdomainCustomDomainAndIsCustomDomainEnabledType,
+    pathname: string,
   ) {
     const url = this.buildWorkspaceURL({
       workspace,
-      pathname: '/verify',
+      pathname,
       searchParams: { errorMessage },
     });