Bug 1911123 - Add configurable description text for checklist items in about:welcome MultiSelect component r=omc-reviewers,jprickett
These changes support an upcoming opt-out telemetry experiment that requires descriptions for certain items in the aboutwelcome MultiSelect template.
Margins, padding, font size, and other [[ https://searchfox.org/mozilla-central/source/browser/components/aboutwelcome/content-src/components/MSLocalized.jsx#6-18 | configurable styles ]] can be adjusted for the title, subtitle, labels, and description text to best fit a given message.
**LTR**
{F7498988}
**RTL**
{F7498984}
**RDM**
{F7499309}
**Full split with wrapping label (might occur in some languages)**
{F7499811}
Differential Revision: https://phabricator.services.mozilla.com/D218342
26fd29a83b