docs: update docs on insecure route behaviour to match reality

[rocketeerbkw]

General Checklist

• Affected Issues have been mentioned in the Closing issues section
• Documentation has been written/updated
• PR title is ready for inclusion in changelog

Database Migrations

n/a

Description

Updates docs about insecure routes. Fixes references to default values, example code in docs, and references to deprecated options.

Closing issues

• Depends on feat: align default values for autogen/custom routes insecure behavior build-deploy-tool#449
• Closes Docs: Insecure redirect defaults #3648

[shreddedbacon]

This makes sense as long as uselagoon/build-deploy-tool#449 is confirmed. Need more data collected on if this would be breaking or not.