postPurchaseAbTestConclude

End a running post-purchase A/B test: its winner takes its place in the live flow at once, for every order from now on, and this can’t be undone. It is the only way a running test leaves the flow. Null if the test doesn’t exist, or belongs to another store. POST_PURCHASE_FLOW_REVISION_STALE (409) when the flow changed since expectedRevision: a running test keeps running, so read the flow and call again with the new revision; INVALID_POST_PURCHASE_REQUEST (400) for a treatment that isn’t in the test, or a test that hasn’t started. CONVERSION_FEATURE_LOCKED (409) when post-purchase is locked for the store. POST_PURCHASE_FLOW_UNREADABLE (409) when the stored flow can’t be read.