Fix sentry error (#5848)

Fixes
https://twenty-v7.sentry.io/issues/5363536663/?environment=prod&project=4507072499810304&query=is%3Aunresolved+issue.priority%3A%5Bhigh%2C+medium%5D&referrer=issue-stream&statsPeriod=7d&stream_index=0

- handle error properly in twenty-server
- display backend error message

packages/twenty-server/src/engine/core-modules/auth/auth.resolver.ts

@@ -82,9 +82,15 @@ export class AuthResolver {
   async findWorkspaceFromInviteHash(
     @Args() workspaceInviteHashValidInput: WorkspaceInviteHashValidInput,
   ) {
-    return await this.workspaceRepository.findOneBy({
+    const workspace = await this.workspaceRepository.findOneBy({
       inviteHash: workspaceInviteHashValidInput.inviteHash,
     });
+
+    if (!workspace) {
+      throw new BadRequestException('Workspace does not exist');
+    }
+
+    return workspace;
   }
 
   @UseGuards(CaptchaGuard)