[NFC] Add in more assertions around the content of line items and tot…

[seamuslee001]

…al amount of the contribution record

Overview

This PR adds in some more assertions to the changed fee selection test around the values of the line items

Before

Less assertions

After

more assertions

ping @eileenmcnaughton

[civibot]

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[eileenmcnaughton]

@seamuslee001 this adds testing so it's OK to merge - but note I've been trying to add in the validateAllPayments to these tests - #16118 - I think my adding might have stalled on the same bug where changeFeeSelection is not correctly creating data for one row

[eileenmcnaughton]

Looks like the same test

[eileenmcnaughton]

Also note that if we are working in this area we need to keep working on https://docs.civicrm.org/dev/en/latest/financial/financialentities/