refactor: initialising pop drink session.

[Daanvdplas]

Taking inspiration from new_test().execute_with(|| { }), an improvement might be to define something similar in pop-drink which takes the session and contract details as parameters and then has a function for executing a closure, with the session and contract address as the closure parameters.

https://github.com/r0gue-io/pop-node/pull/300/files/bea0e9aa4b9f9e231b2be5ad25f974bf290913fc#r1778408231