Fix the remainder of the cookie links

Fixes https://github.com/vector-im/riot-web/issues/10362

Per https://github.com/vector-im/riot-web/pull/11998#issuecomment-577329852

electron_app/riot.im/config.json

@@ -22,7 +22,7 @@
     "piwik": {
         "url": "https://piwik.riot.im/",
         "siteId": 1,
-        "policyUrl": "https://matrix.org/docs/guides/riot_im_cookie_policy"
+        "policyUrl": "https://matrix.org/legal/riot-im-cookie-policy"
     },
     "phasedRollOut": {
         "feature_lazyloading": {

riot.im/app/config.json

@@ -35,7 +35,7 @@
             "text": "Privacy Policy"
         },
         {
-            "url": "https://matrix.org/docs/guides/riot_im_cookie_policy",
+            "url": "https://matrix.org/legal/riot-im-cookie-policy",
             "text": "Cookie Policy"
         }
     ]

riot.im/develop/config.json

@@ -47,7 +47,7 @@
             "text": "Privacy Policy"
         },
         {
-            "url": "https://matrix.org/docs/guides/riot_im_cookie_policy",
+            "url": "https://matrix.org/legal/riot-im-cookie-policy",
             "text": "Cookie Policy"
         }
     ]