[PRD/Requirements]: Update Contact Us Page to Align with CUJ

[amywlchong]

Description of the problem

The /contact page is currently not aligned with Critical User Journeys for Web (External Users) -- v3
CUJs: https://docs.google.com/spreadsheets/d/1IrxN13IC5xwWdAFnGMu_4p3FU1ADL4QO-eLZIuTowIA/edit?gid=959027794#gid=959027794

Possible solutions / ideas for addressing the problem

• There is an explicit, welcoming channel/label for "Parent / User Support" alongside the partner/donor channels. There is an embedded contact form on the page that emails admin@oppia.org when submitted.

Any other relevant context/info

No response