Fix phoenix at 1.6.2

According to https://github.com/phoenixframework/phoenix/issues/4623 , 1.6.2 seems to not have the disconnection bug.

Replaces !1485 (closed)

package.json

@@ -34,6 +34,7 @@
     "localforage": "1.10.0",
     "parse-link-header": "1.0.1",
     "phoenix": "1.4.0",
+    "phoenix": "1.6.2",
     "punycode.js": "2.1.0",
     "qrcode": "1",
     "ruffle-mirror": "2021.12.31",