* Eliminates AB.js dependency on sticky header
* Code coverage has been raised to 100%
* Instead of importing ABTestConfig, these props are now passed into the
function along with a token.
* WikimediaEvents hook is now fired when experiment is initialized. The
experiment should not be initialized if it is not enabled.
* Removes several methods (e.g. initAB, getEnabledExperiment) due to the
preceeding changes.
* Adds `isInSample` and `isInTreatmentBucket` methods so that the client
has less work.
Treatment buckets now follow a naming convention so that the client can
do less work querying if the subject is part of the treatment:
* Treatment buckets should have the case-insensitive `treatment`
substring somewhere in their name (e.g. 'treatment',
'stickyHeaderTreatment', 'sticky-header-treatment' )
Bug: T302046
Change-Id: I4febec42b4c471b2f2ef02be2e334bd6d2c31eec
