Add a har for gh_new_pr

Author: nedtwigg

browser-extension/tests/har-index.ts

@@ -1,5 +1,7 @@
 export const PAGES = {
   gh_issue: 'https://github.com/diffplug/selfie/issues/523',
   gh_new_issue: 'https://github.com/diffplug/selfie/issues/new',
+  gh_new_pr:
+    'https://github.com/diffplug/selfie/compare/main...cavia-porcellus:selfie:main?expand=1',
   gh_pr: 'https://github.com/diffplug/selfie/pull/517',
 } as const