feat(errors): fix error handling for connection and conference

Properly handle errors while connecting or joining a conference. Prior to this
patch, only errors on established conferences / connections were saved to the
redux store.

react/features/base/conference/reducer.js

  * reduction of the specified action.
  */
 function _conferenceFailed(state, { conference, error }) {
-    if (state.conference && state.conference !== conference) {
+    // The active conference or the one we are joining.
+    const conference_ = state.conference || state.joining;
+
+    if (conference_ && conference_ !== conference) {
         return state;
     }
 

react/features/base/connection/reducer.js

             connection: Object,
             error: Object | string
         }) {
-    if (state.connection && state.connection !== connection) {
+
+    // The active or in-progress connection.
+    const connection_ = state.connecting || state.connection;
+
+    if (connection_ && connection_ !== connection) {
         return state;
     }