kraken: use new `Position.mkt` attr

piker/brokers/kraken/broker.py

@@ -402,7 +402,7 @@ def trades2pps(
                 # right since `.broker` is already
                 # included?
                 account='kraken.' + acctid,
-                symbol=p.symbol.fqme,
+                symbol=p.mkt.fqme,
                 size=p.size,
                 avg_price=p.ppu,
                 currency='',

piker/brokers/kucoin.py

@@ -647,7 +647,6 @@ async def get_mkt_info(
             tx_tick=digits_to_dec(dst.precision),
             info=dst.to_dict(),
         )
-
         mkt = MktPair(
             dst=dst_asset,
             src=src_asset,

piker/clearing/_paper_engine.py

@@ -578,8 +578,7 @@ async def trades_dialogue(
 
         # for each sym in the ledger load it's `MktPair` info
         for tid, txdict in ledger.data.items():
-            # TODO: switch this to fqme
-            l_fqme = txdict.get('fqme', txdict['fqsn'])
+            l_fqme: str = txdict.get('fqme') or txdict['fqsn']
 
             if (
                 gmi