Request notifications permission on Subscape banner click

This shows the notification request over the Subscape loading page,
which may not be the final form of the request.

ui/components/Wallet/Banner/PortalBanner.tsx

@@ -13,6 +13,7 @@ export default function PortalBanner(): ReactElement | null {
   const hasIslandAssets = useBackgroundSelector(selectHasIslandAssets)
 
   const showIslandAndDismissBanner = () => {
+    browser.permissions.request({ permissions: ["notifications"] })
     browser.tabs.create({ url: "https://app.taho.xyz" })
   }