Audit and fix our use of the "title" attribute in components

From #2558

Julien wrote:
> This is optional as we can improve in follow-ups and we use title in other places too, but this is problematic because the accessibility of this content is bad and there's no other location where it's shown.
See https://developer.paciellogroup.com/blog/2013/01/using-the-html-title-attribute-updated/ for more background on this, and https://inclusive-components.design/tooltips-toggletips/ for some alternatives (our own tooltip implementation isn't so good either).

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-277)