Modified Permissions Flow (#1005)

Permissions flow for Android was causing the white screen on initial permission grant on occasion. Moved permission grant to pre-TOTP page load.

src/App/Utilities/PermissionManager.cs

@@ -0,0 +1,21 @@
+using System.Threading.Tasks;
+using Xamarin.Essentials;
+using static Xamarin.Essentials.Permissions;
+
+namespace Bit.App.Utilities
+{
+    public static class PermissionManager
+    {
+        public static async Task<PermissionStatus> CheckAndRequestPermissionAsync<T>(T permission)
+            where T : BasePermission
+        {
+            var status = await permission.CheckStatusAsync();
+            if (status != PermissionStatus.Granted)
+            {
+                status = await permission.RequestAsync();
+            }
+
+            return status;
+        }
+    }
+}