fix: add Page.getDefaultTimeout getter

[GuillaumeGomez]

Fixes #8901.

[conventional-commit-lint-gcf]

🤖 I detect that the PR title and the commit message differ and there's only one commit. To use the PR title for the commit history, you can use Github's automerge feature with squashing, or use automerge label. Good luck human!

-- conventional-commit-lint bot
https://conventionalcommits.org/

[OrKoN]

You'd need to run npm run docs locally to regenerate markdown docs, and commit them or the check jobs will complain

[GuillaumeGomez]

Done as well.

[GuillaumeGomez]

Thanks for the quick review and your help!