doEventActionSideEffects [nfc]: Remove message-event handler.

This was a lot of setup for the in-app "notification" sound, which
we removed in a recent commit.

src/events/doEventActionSideEffects.js

@@ -1,58 +1,18 @@
 /* @flow strict-local */
 // import { Vibration } from 'react-native';
 
-import { AppState } from 'react-native';
-import type { GlobalState, Message, ThunkAction } from '../types';
+import type { ThunkAction } from '../types';
 import type { EventAction } from '../actionTypes';
-import { EVENT_NEW_MESSAGE, EVENT_TYPING_START } from '../actionConstants';
-import { isHomeNarrow, isMessageInNarrow } from '../utils/narrow';
-import { getActiveAccount, getChatScreenParams } from '../selectors';
-import { NULL_ARRAY } from '../nullObjects';
+import { EVENT_TYPING_START } from '../actionConstants';
 import { ensureTypingStatusExpiryLoop } from '../typing/typingActions';
-import { getOwnUserId } from '../users/userSelectors';
-
-/**
- * React to incoming `MessageEvent`s.
- */
-const messageEvent = (state: GlobalState, message: Message): void => {
-  const flags = message.flags ?? NULL_ARRAY;
-
-  if (AppState.currentState !== 'active') {
-    return;
-  }
-
-  const isMentioned = flags.includes('mentioned') || flags.includes('wildcard_mentioned');
-  if (!(message.type === 'private' || isMentioned)) {
-    return;
-  }
-
-  const activeAccount = getActiveAccount(state);
-  // Assume (unchecked) that `narrow` is `Narrow` if present
-  // $FlowFixMe[cannot-resolve-name]
-  const narrow: Narrow | void = getChatScreenParams().narrow;
-  const isUserInSameNarrow =
-    activeAccount
-    && narrow !== undefined // chat screen is not at top
-    && !isHomeNarrow(narrow)
-    && isMessageInNarrow(message, flags, narrow, getOwnUserId(state));
-  const isSenderSelf = getOwnUserId(state) === message.sender_id;
-  if (!isUserInSameNarrow && !isSenderSelf) {
-    // Vibration.vibrate();
-  }
-};
 
 /**
  * React to actions dispatched for Zulip server events.
  *
  * To be dispatched before the event actions are dispatched.
  */
 export default (action: EventAction): ThunkAction<Promise<void>> => async (dispatch, getState) => {
-  const state = getState();
   switch (action.type) {
-    case EVENT_NEW_MESSAGE: {
-      messageEvent(state, action.message);
-      break;
-    }
     case EVENT_TYPING_START:
       dispatch(ensureTypingStatusExpiryLoop());
       break;