Move instances of Client.uploadFile() in components to an action (#5165)

webapp/actions/file_actions.jsx

@@ -0,0 +1,26 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+import * as AsyncClient from 'utils/async_client.jsx';
+import Client from 'client/web_client.jsx';
+
+export function uploadFile(file, name, channelId, clientId, success, error) {
+    Client.uploadFile(
+        file,
+        name,
+        channelId,
+        clientId,
+        (data) => {
+            if (success) {
+                success(data);
+            }
+        },
+        (err) => {
+            AsyncClient.dispatchError(err, 'uploadFile');
+
+            if (error) {
+                error(err);
+            }
+        }
+    );
+}