Update user context and request related docs

Summary of change

Updates existing docs to not read usercontext[_default][request] and use the new helper function instead
Adds a new page that explains how to get the request object from user context and how that can be used
Updates existing user context docs to link to the new page

[ ] Algolia search needs to be updated? (If there is a new sub docs project, then yes)
[ ] Sitemap needs to be updated? (If there is a new sub docs project, then yes)
[ ] Checked for broken links? (Run cd v2 && MODE=production npx docusaurus build)
[ ] Changes required to the demo apps corresponding to the docs?

Name	Link
Latest commit	cd89e461a5e063bd4ec0befb4ddbbe32f64ca880
Latest deploy log	https://app.netlify.com/sites/admiring-bhabha-7b1be9/deploys/646df3307f448e0008511b67