dev/core#1049: Use FrontEndPaymentFormTrait to assign line items…

[agileware-fj]

… on Event Registration Confirm and ThankYou "forms"

Overview

Code cleanup around tax assignments, following pattern on #13899 but for Event Confirmation and ThankYou pages
Agileware ref CIVICRM-1244

Before

Event Confirmation and ThankYou Forms are implementing their own line item assignments, causing inconsistency in line item display. This is most immediately obvious in the tax rate column when tax & invoicing is enabled

After

These Forms use the previously implemented trait to assign line items in a consistent manner.

[civibot]

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[agileware-fj]

Also see #14563 for rc PR

[mattwire]

@agileware-fj Thanks for doing this. From a code POV this looks ok. If someone is able to do an R-RUN and confirm that all is well then we can merge - @alifrumin @lcdservices @michaelmcandrew

[lcdservices]

I enabled taxes, setup a tax Financial Account, assigned it to the Event Fee Financial Type, and tested an event with multiple price fee fields. The confirmation and thank you pages were accurate and looked great.

[seamuslee001]

Based on @mattwire 's comment and @lcdservices 's r-run i'm going to merge thanks @agileware-fj