Estimate XCM fees for all integration tests

[franciscoaguirre]

We should estimate XCM fees correctly in all integration tests now that we have the DryRunApi and XcmPaymentApi.
Right now, we assert balances at the end of a transfer are less than or greater than what they were before.
We could do much better and use equality for these asserts, making use of the estimation APIs.

To do this, we can integrate it on the xcm-emulator.