[REF] Remove never-passed param from getLineItems

[eileenmcnaughton]

Overview

Minor tidy up in getLineItems

Before

$invoice is in fn signature & has handling in fn but is never used

After

Parameter $invoice fully removed

Technical Details

Parameter was added to getLineItems in 25d0c64
to support invoicing. However that function no longer calls getLineItems & has not for some time (at least a year). No other functions
pass in this parameter so we can remove it_

Comments

The code comment suggests something might be broken here but it broke a long time ago & had no tests so at this stage we should clean it up & if comes back with tests then all good.

[civibot]

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[yashodha]

@eileenmcnaughton Why is the additional participant bit removed as well?

[eileenmcnaughton]

@yashodha because the if clause is

if ($entity == 'participant' && $invoice) {

If $invoice is never true the whole IF is never true