[FEAT] add default verdict when no approver is available

[edwinkys]

Feature Description

Currently, when there is no approver connected to the coordinator server, the receiver server will return an error back to the client. We want to add a configuration that allows the receiver server to auto-approve in case no approver is available.

Potential Solution

• Set environment variable for this configuration.
• When get approval method is call, we check for this configuration and return accordingly.