[e.cash] camel case hrefLang tag

Summary:
Patch reported warning with hreflang patch

hreflang is lowercase in html but camel case in jsx

Test Plan: npm test, npm run dev , navigate to site in browser, no warning

Reviewers: #bitcoin_abc, johnkuney

Reviewed By: #bitcoin_abc, johnkuney

Subscribers: johnkuney

Differential Revision: https://reviews.bitcoinabc.org/D14341