fix some flow

src/actions/LocalStorageActions.js

@@ -363,8 +363,8 @@ export const handleCoinVisibility = (
     coinShortcut: String,
     shouldBeVisible: boolean
 ): ThunkAction => (dispatch: Dispatch): void => {
-    const configuration: ?Array<String> = getHiddenCoins();
-    let newConfig = configuration;
+    const configuration: Array<String> = getHiddenCoins();
+    let newConfig: Array<String> = configuration;
     const isAlreadyHidden = configuration.find(coin => coin === coinShortcut);
 
     if (isAlreadyHidden && shouldBeVisible) {

src/actions/WalletActions.js

@@ -25,6 +25,10 @@ export type WalletAction =
           state?: RouterLocationState,
           pathname?: string,
       }
+    | {
+          type: typeof WALLET.SET_HIDDEN_COINS,
+          hiddenCoins: Array<String>,
+      }
     | {
           type: typeof WALLET.TOGGLE_DEVICE_DROPDOWN,
           opened: boolean,