bug: get_subscriptions_by_account_and_maybe_app query runs slow sometimes

[chris13524]

Make A/B testing framework

Faster query perhaps here: https://walletconnect.slack.com/archives/C04SYT4LU2W/p1712948291488419

Maybe need to store read count as a column rather than counting each time.

[linear]

W3I-73 bug: get_subscriptions_by_account_and_maybe_app query runs slow sometimes