REF Extract override default currency function

[mattwire]

Overview

Simple extraction of duplicated code to a single shared function

Before

Same code duplicated

After

Same code in single function

Technical Details

There is an open question as to whether this code is actually required at all. But let's start by extracting it to one place.

Comments

[civibot]

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[eileenmcnaughton]

@mattwire sell jenkins on it & this is good to go. I went through the code changes line by line