Add contribution id as activity source record when downloading or emailing invoice

[pradpnayak]

Overview

When a invoice is emailed or downloaded CiviCRM creates activity of type 'Emailed Invoice' or 'Downloaded Invoice' respectively. These activities has missing source record and have no ways to reference to contribution other than viewing the activity , checking the attached invoice to find invoice number and so on.

This PR adds source record as contribution id in activity params so that it can be referenced in future.

Before

Activity source id was set to null for activity type 'Emailed Invoice' or 'Downloaded Invoice'

After

Activity source id was set to contribution id for activity type 'Emailed Invoice' or 'Downloaded Invoice'

[civibot]

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[eileenmcnaughton]

Seems OK to me - we should really use apiv4 not 3 but I think we can leave that for now