Remove extra / from host uri in UrlHelper.addHost

Author: Sam1301

app/src/main/java/com/zulip/android/util/UrlHelper.java

@@ -6,7 +6,12 @@ public class UrlHelper {
 
     public static String addHost(String url) {
         if (!url.startsWith("http")) {
-            url = ZulipApp.get().getServerHostUri() + url;
+            String hostUrl = ZulipApp.get().getServerHostUri();
+            if (hostUrl.endsWith("/")) {
+                url = hostUrl.substring(0, hostUrl.length() - 1) + url;
+            } else {
+                url = hostUrl + url;
+            }
         }
 
        return url;