We will want to display a corrected five star rating for products in the sidebar.

It turns out there's already a FiveStarRating component used by the about:addons code.

Let's pull that component out into the reusable components in toolkit/content/widgets, and then reuse that component to render the star rating for shopping.

There should be some unit-y tests that check that the markup for a given API response is what we expect.

Backed out for causing failures related to moz-five-star.css

• backout: https://hg.mozilla.org/integration/autoland/rev/af459eb5d80fb399f9000c09baf10314105b4cdb
• push: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&selectedTaskRun=SE_6kjVmS_CtJkD1C2PKjg.0&revision=361e7d6f9080687808101d9703d0e23b06d19314
• failure log: https://treeherder.mozilla.org/logviewer?job_id=420339394&repo=autoland&lineNumber=2328

[task 2023-06-22T20:23:20.079Z] 20:23:20     INFO - Ignored error "Unknown pseudo-class or pseudo-element ‘-moz-native-anonymous’.  Ruleset ignored due to bad selector." on resource://gre-resources/ua.css because of whitelist item {"sourceName":"/\\b(contenteditable|EditorOverride|svg|forms|html|mathml|ua)\\.css$/i","errorMessage":"/Unknown pseudo-class.*-moz-/i","isFromDevTools":false,"used":true}
[task 2023-06-22T20:23:20.079Z] 20:23:20     INFO - Buffered messages finished
[task 2023-06-22T20:23:20.080Z] 20:23:20     INFO - TEST-UNEXPECTED-FAIL | browser/base/content/test/static/browser_parsable_css.js | Got error message for chrome://global/content/elements/moz-five-star.css: Unknown pseudo-class or pseudo-element ‘has’.  Ruleset ignored due to bad selector. - 
[task 2023-06-22T20:23:20.080Z] 20:23:20     INFO - Stack trace:
[task 2023-06-22T20:23:20.080Z] 20:23:20     INFO - chrome://mochikit/content/browser-test.js:test_ok:1580
[task 2023-06-22T20:23:20.080Z] 20:23:20     INFO - chrome://mochitests/content/browser/browser/base/content/test/static/browser_parsable_css.js:messageIsCSSError:286
[task 2023-06-22T20:23:20.081Z] 20:23:20     INFO - chrome://mochitests/content/browser/browser/base/content/test/static/browser_parsable_css.js:checkAllTheCSS:556
[task 2023-06-22T20:23:20.081Z] 20:23:20     INFO - chrome://mochikit/content/browser-test.js:handleTask:1131
[task 2023-06-22T20:23:20.081Z] 20:23:20     INFO - chrome://mochikit/content/browser-test.js:_runTaskBasedTest:1203
[task 2023-06-22T20:23:20.081Z] 20:23:20     INFO - chrome://mochikit/content/browser-test.js:Tester_execTest:1345
[task 2023-06-22T20:23:20.081Z] 20:23:20     INFO - chrome://mochikit/content/browser-test.js:nextTest/<:1120
[task 2023-06-22T20:23:20.081Z] 20:23:20     INFO - chrome://mochikit/content/tests/SimpleTest/SimpleTest.js:SimpleTest.waitForFocus/<:1056

https://hg.mozilla.org/mozilla-central/rev/d9a4950d4447

In https://hg.mozilla.org/mozilla-central/rev/d9a4950d4447#l8.12 you're referring to a browser/ fluent file from toolkit/. This seems to be breaking some Thunderbird functionality. Can that be moved to toolkit?