#1015 fix regression on exporting soft credits - more robust version

This applies a full fix to a regression we fixed with a less robust fix due to test issues
https://github.com/civicrm/civicrm-core/pull/13748/commits/7f59431188688d4697bff55738fe17996abe442f#diff-e54381bfdf51e31cab376c71ca0d66ffR2716
removed a space that was required when exporting soft credits. The fix makes the addition of a space in
a more sensible way (doesn't rely on it being done correctly in dozens of places