Remove superfluous database calls in deliver_email and send_email

[jimleroyer]

Description

As a user of GCNotify,
I want my emails to be sent quick,
So that I can have a super service sending emails real quick.

As a developer of GCNotify,
I want to clean up house around the performance of network and database calls in the deliver_email and send_email functions,
So that I can get faster performance for the email delivery.

WHY are we building?

Optimize speed on our sending delivery code path.

WHAT are we building?

We can speed up the deliver_email code before the send_email call by removing superfluous database calls. There are related caching performance improvements as well that this function would benefit from.

GDS did improvements that show what can be done. These improvements are described in more details in this task.

This suggestion comes from our ADR on Scalability: increasing send rates.

VALUE created by our solution

Email delivery speed.

Acceptance Criteria

• Sending emails is faster.

QA Steps

• Run the rollercoaster test before and after the change to compare the time differences.