Incorrect status about globally settled prediction markets

**Describe the bug**

The prediction market `BTS2020FEB` has been globally settled at price `0`, but
1. the "Settlement" section in the asset info page doesn't show the correct status. See https://wallet.bitshares.org/#/asset/BTS2020FEB/
2. holders can not force-settle in bitshares-ui (although a holder would get nothing by settling, the tooltip / warning should indicate it correctly). See https://wallet.bitshares.org/#/account/bitg

Start by reproducing the settlement display at the asset info page and the force-settlement behavior at the account page linked in the issue. Trace the UI entry points that determine global settlement status and the related tooltip or warning. Done means BTS2020FEB shows its global settlement at price 0 correctly and the force-settlement messaging accurately explains the outcome.

Written by the indexing model from the issue text.