fix: Donot use cache in getByChannelUrl

* getByChannelUrl cache is disabled by default
* getByChannelUrl has two interfaces now:
```
getByChannelUrl(channelUrl: string, callback: TicketCallback): void;
getByChannelUrl(channelUrl: string, cachingEnabled: boolean , callback: TicketCallback): void;
```
* To use caching, use 2nd interface

Because there is no real time communication,
it doesnt really make sense to implement caching in Ticket API
To implement caching perfectly, we need to implement realtime
event handling.

Author: Sravan S

SendBird.Desk.d.ts

@@ -104,6 +104,7 @@ declare namespace SendBirdDesk {
     ): void;
     getOpenCount(callback: CommonCallback): void;
     getByChannelUrl(channelUrl: string, callback: TicketCallback): void;
+    getByChannelUrl(channelUrl: string, cachingEnabled: boolean , callback: TicketCallback): void;
     getAllTickets(offset: number, callback: TicketArrayCallback): void;
     getAllTickets(offset: number, customFieldFilter: object, callback: TicketArrayCallback): void;
     getOpenedList(offset: number, callback: TicketArrayCallback): void;

SendBird.Desk.min.js

@@ -1,6 +1,6 @@
 {
   "name": "sendbird-desk",
-  "version": "1.0.21",
+  "version": "1.0.22",
   "description": "SendBird Desk SDK Integration Guide for JavaScript =========== SendBird Desk is a chat customer service platform built on SendBird SDK and API.",
   "main": "SendBird.Desk.min.js",
   "scripts": {