Revert "ve.init.mw.trackSubscriber: Populate platform field with hack"

Caused JS errors when invoked too early.

This reverts commit 35d38985439dddf54b5001d569e82c9d719e7c6a.

Change-Id: Ie7dd4ef8323a16bb694e6300a096ba53cf4a0a91
Merge "Revert "ve.init.mw.trackSubscriber: Populate platform field with hack""