cmd/tsconnect: update to xterm.js 5.1

It includes xtermjs/xterm.js#4216, which improves handling of some
escape sequences. Unfortunately it's not enough to fix the issue
with `ponysay`, but it does not hurt to be up to date.

Updates #6090

Signed-off-by: Mihai Parparita <mihai@tailscale.com>

cmd/tsconnect/package.json

@@ -10,9 +10,9 @@
     "qrcode": "^1.5.0",
     "tailwindcss": "^3.1.6",
     "typescript": "^4.7.4",
-    "xterm": "^5.0.0",
-    "xterm-addon-fit": "^0.6.0",
-    "xterm-addon-web-links": "^0.7.0"
+    "xterm": "^5.1.0",
+    "xterm-addon-fit": "^0.7.0",
+    "xterm-addon-web-links": "^0.8.0"
   },
   "scripts": {
     "lint": "tsc --noEmit",