fix: ability to open a new tab on iOS Safari (#1516)

* fix: ability to open a new tab on iOS Safari

* chore: fix `https deprecation` warning

* chore: better variable naming

packages/web/src/javascripts/Utils/ManageSubscription.ts

@@ -1,13 +1,14 @@
 import { SNApplication } from '@standardnotes/snjs'
 
 export function openSubscriptionDashboard(application: SNApplication): void {
+  const windowProxy = window.open('', '_blank')
   application
     .getNewSubscriptionToken()
     .then((token) => {
       if (!token) {
         return
       }
-      window.open(`${window.dashboardUrl}?subscription_token=${token}`)
+      ;(windowProxy as WindowProxy).location = `${window.dashboardUrl}?subscription_token=${token}`
     })
     .catch(console.error)
 }