fix(server): seat not allocated when new user invited to licensed workspace (#12322)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **Bug Fixes**
  - Improved the accuracy of workspace member overcapacity calculation.
  - Corrected seat allocation handling for one-time license variants, ensuring proper event emission and bypassing unnecessary updates.

- **Refactor**
  - Streamlined internal logic by removing an obsolete method related to seat count checks.

- **Tests**
  - Removed a workspace member list pagination test to streamline end-to-end testing.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/models/workspace-user.ts

@@ -289,15 +289,6 @@ export class WorkspaceUserModel extends BaseModel {
     });
   }
 
-  async insufficientSeatMemberCount(workspaceId: string) {
-    return this.db.workspaceUserRole.count({
-      where: {
-        workspaceId,
-        status: WorkspaceMemberStatus.NeedMoreSeat,
-      },
-    });
-  }
-
   async getUserActiveRoles(
     userId: string,
     filter: { role?: WorkspaceRole } = {}