[REF] [towards dev/core#2693] Use getter rather than passing variable

[eileenmcnaughton]

Overview

[REF] Use getter rather than passing variable

Before

Array key set & passed around

After

Consistently retrieved as needed

Technical Details

txnType is a required parameter for recurring & unused for single. This switches to retrieving
it as needed rather than passing it around. It removes one check for whether it is
set because the abort will exit if not

Comments

[civibot]

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[eileenmcnaughton]

unrelated fail