message: Searching: Return an empty result if the search term is an empty string.
  This mimics the behaviour we get from synapse as, this fixes
diff: @@ -87,6 +87,13 @@ async function localSearch(searchTerm, roomId = undefined) {
  searchArgs.room_id = roomId;
  }
  + const emptyResult = {
  + results: [],
  + highlights: [],
  + };
  +
  + if (searchTerm === "") return emptyResult;
  +
  const eventIndex = EventIndexPeg.get();
  const localResult = await eventIndex.search(searchArgs);
  @@ -97,11 +104,6 @@ async function localSearch(searchTerm, roomId = undefined) {
  },
  };
  - const emptyResult = {
  - results: [],
  - highlights: [],
  - };
  -
  const result = MatrixClientPeg.get()._processRoomEventsSearch(
  emptyResult, response);
  