Add isBackOffice, isPayLater, getPaymentMode helpers to frontendpaymentformtrait

[mattwire]

Overview

This adds helper functions and properties to frontendpaymentformtrait for isBackOffice(), isPayLater() and get/SetPaymentMode() so we don't have to interact directly with the properties and do not have to specify them on each form.

Developed for #17508

Before

Direct access to properties, they must be specified on each form.

After

Just use frontendpaymentformtrait and the new methods.

Technical Details

Comments

[civibot]

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[seamuslee001]

Jenkins re test this please

[eileenmcnaughton]

I agree with this change - let's see the warning fix & check tests pass & then I think it should be OK to merge.

You could possibly deprecate $_mode - but then I think you'd need another undeprecated protected property that would also be set & returned. We have tried that elsewhere - with some degree of success (non-blocking feedback)

[seamuslee001]

Jenkins re test this please