Fix browser extension flaky e2e tests

Created by: erzhtor

Seems like the browser extension e2e test for checking the Hover popup -> "Go to definition" -> href is flaky, because it gets updated.

Updated to use the similar approach from original hover regression tests: https://sourcegraph.com/github.com/sourcegraph/sourcegraph/-/blob/client/web/src/regression/codeintel.test.ts?L382

How to test

• sg test bext-build
• sg test bext-e2e