Revert "[refs laterpay/laterpay#550] Ensuring ID is present in flows created with state"

This reverts commit 139e2984a2f048a8e78dcb05ff1d85e1494f0740.
Revert "Adding (this is a really bad idea) initial_state for flows [refs laterpay/laterpay#550]"

This reverts commit f3d834075c0159df2ce0d67782048044ad6ca539.