Include offer letters for offer approvals

Offer letters can now be included in an offer approval process so that the generated offer letter is considered in an approver's decision. This helps keep the candidate's offer data aligned with the offer letter sent to the candidate.

The offer letter appears in the in-app approval view, which is also attached to approval request emails.

Here's an example of the offer letter approval view in-app:

Here's an example of the offer approval email notification, showing where the offer letter is attached:

In the Slack notification, the offer letter is added in the post's thread: