fix: don't report failed network requests as JavaScript errors (#38732)

On the issue ref popup, when the user clicks the link while fetch is
loading, the page will briefly render a network error message before
loading the next page. Suppress unnecessary network errors.

package.json

@@ -49,6 +49,7 @@
     "easymde": "2.21.0",
     "esbuild": "0.28.1",
     "idiomorph": "0.7.4",
+    "is-network-error": "1.3.2",
     "jquery": "4.0.0",
     "js-yaml": "5.2.2",
     "katex": "0.18.1",