fix: Throttle Signup limit on production

[dati18]

No description provided.

[m90]

Note that while the change only touches the production file, it will also affect staging, so we need to apply it to both envs after merging.

[m90]

I also just double checked and we're now at 3 sign ups in the last 24h, which means this is good to go.

>>> User::where('created_at', '>=', \Carbon\Carbon::now()->sub(new \DateInterval('PT24H')))->count()
=> 3