Planner tests: Delegate action

[grod220]

Write tests for delegation action:

web/packages/wasm/crate/src/planner.rs

Lines 345 to 356 in 8bf66ea

	for tpr::Delegate { amount, rate_data } in request.delegations {
	let epoch = storage.get_latest_known_epoch().await?.unwrap();
	let amount = amount
	.ok_or_else(|| anyhow!("missing amount in delegation"))?
	.try_into()?;
	let rate_data: RateData = rate_data
	.ok_or_else(|| anyhow!("missing rate data in delegation"))?
	.try_into()?;
	let delegate = rate_data.build_delegate(epoch.into(), amount);
	actions_list.push(delegate);
	}