Revert "Convert BuildIgnoreApexContritbutions variable to a boolean"

This revert was created by Android Culprit Assistant. The culprit was identified in the following culprit search session (http://go/aca-get/53721efb-c49e-4ce8-b96c-fd03598b4202).

Change-Id: I197b03b650bc6c22ff3c5eb9605522fd9650e98f