NMI: Compact before joining authorization

[lscoates]

Description

When generating the authorization in authorization_from, it is possible for params[:payment] to be nil, which appends a "#" to the end of the transaction_id. This PR adds compact when calling authorization_from to handle this case.

Ref: A similar pattern exists here: https://github.com/activemerchant/active_merchant/blob/master/lib/active_merchant/billing/gateways/efsnet.rb#L163

Tests

# Remote Tests
33 tests, 106 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed

# Unit Tests
27 tests, 194 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed