Merge pull request #7894 from BitGo/BTC-0.fix-express-typed

fix(express): allow string for feeRate

Author: davidkaplanbitgo

modules/express/src/typedRoutes/api/v2/sendCoins.ts

@@ -67,7 +67,7 @@ export const SendCoinsRequestBody = {
   numBlocks: optional(t.number),
 
   /** The desired fee rate for the transaction in base units per kilobyte (e.g., satoshis/kB) */
-  feeRate: optional(t.number),
+  feeRate: optional(t.union([t.number, t.string])),
 
   /** Fee multiplier (multiplies the estimated fee by this factor) */
   feeMultiplier: optional(t.number),