Fix EscrowUtils to return null if escrow is not found

Author: flopez7

packages/sdk/typescript/human-protocol-sdk/src/escrow.ts

@@ -1958,9 +1958,12 @@ export class EscrowUtils {
       GET_ESCROW_BY_ADDRESS_QUERY(),
       { escrowAddress: escrowAddress.toLowerCase() }
     );
+    if (!escrow) {
+      return null;
+    }
     escrow.chainId = networkData.chainId;
 
-    return escrow || null;
+    return escrow;
   }
 
   /**