fix(gum): add electron string for requesting gum permissions

Electron generally can bypass having to get permission for
audio and video. In the case it doesn't have it, and the
permission screen is displayed, a string should still display
prompting the user to click allow. Right now the string id
displays.

lang/main.json

@@ -23,6 +23,7 @@
       "react-nativeGrantPermissions": "Select <b><i>Allow</i></b> when your browser asks for permissions.",
       "chromeGrantPermissions": "Select <b><i>Allow</i></b> when your browser asks for permissions.",
       "androidGrantPermissions": "Select <b><i>Allow</i></b> when your browser asks for permissions.",
+      "electronGrantPermissions": "Please grant permissions to use your camera and microphone",
       "firefoxGrantPermissions": "Select <b><i>Share Selected Device</i></b> when your browser asks for permissions.",
       "operaGrantPermissions": "Select <b><i>Allow</i></b> when your browser asks for permissions.",
       "iexplorerGrantPermissions": "Select <b><i>OK</i></b> when your browser asks for permissions.",