Add typings for the har-format lib.

Author: nedtwigg

browser-extension/package-lock.json

@@ -12,6 +12,7 @@
     "@playwright/test": "^1.46.0",
     "@testing-library/jest-dom": "^6.6.4",
     "@types/express": "^4.17.21",
+    "@types/har-format": "^1.2.16",
     "@types/node": "^22.16.5",
     "@vitest/coverage-v8": "^3.2.4",
     "@vitest/ui": "^3.2.4",