Approves an offer or a specific approval step within an offer's approval process.

This endpoint mimics the behavior of the "Force Approve" function in the Ashby app, where an admin can override approval for a specific step or entire approval process.

This endpoint can be used in two ways:

1. Approve entire offer: Call without approvalStepId and userId to approve the entire offer approval process
2. Approve specific step: Provide both approvalStepId and userId to approve a specific step in the approval process

When approving a specific step, the step must be the current step in the approval process and the user must be an approver for that step.

Requires the offersWrite permission.