GUACAMOLE-773: Remove angular-touch (no longer applicable).

Previously, the angular-touch library provided by AngularJS was used to
allow click interactions with UI components to work on touch devices
without an uncomfortable ~300ms delay. From AngularJS 1.7.x onward, this
feature of angular-touch is no longer present:

https://docs.angularjs.org/guide/migration#ngtouch

This should be OK - modern browsers will now recognize applications
aimed at touch support via the use of the "viewport" meta tag (which we
use), removing our original need for angular-touch. The same goes for
IE10+.

guacamole/src/main/frontend/package-lock.json

@@ -544,11 +544,6 @@
                 }
             }
         },
-        "angular-touch": {
-            "version": "1.8.2",
-            "resolved": "https://registry.npmjs.org/angular-touch/-/angular-touch-1.8.2.tgz",
-            "integrity": "sha512-tGoFNsONm/VHFcBW8gySVZvpCIYAvsAlEuHpJDugGn+3ENLxSDhpZ4ikev4KXfWr8ZNsYGoVSfsvJegkiC+9Ig=="
-        },
         "angular-translate": {
             "version": "2.18.4",
             "resolved": "https://registry.npmjs.org/angular-translate/-/angular-translate-2.18.4.tgz",