Fix typos in TypeScript and SCSS files

See [#5136][0].

[0]: https://github.com/signalapp/Signal-Desktop/pull/5136

ts/textsecure/MessageReceiver.ts

@@ -1225,7 +1225,7 @@ class MessageReceiverInner extends EventTarget {
 
       const errorString = error && error.stack ? error.stack : error;
       window.log.error(
-        `maybeLightSessionReset/${id}: Enountered error`,
+        `maybeLightSessionReset/${id}: Encountered error`,
         errorString
       );
     }