Magazine: a11y: Heading elements are not in a sequentially-descending order

[synox]

https://pagespeed.web.dev/analysis/https-main--24life--hlxsites-hlx-live-magazine-volume-6-issue-2/ug14llec2b?form_factor=mobile

in magazine-summary, we should use <p> with classes with font styles, instead of using <h4> and <h6>.