handle objects in snackbar messages

metamask returns objects

src/dapp.js

@@ -80,8 +80,13 @@ class App extends React.Component {
   }
 
   openSnackBar = (variant, message) => {
+    if (typeof message === 'object') {
+      const msg = message.message
+      this.setState({ snackbar: { variant, message: msg } })
+    } else {
       this.setState({ snackbar: { variant, message } })
     }
+  }
 
   closeSnackBar = () => {
     this.setState({ snackbar: null })