test(MarkdownEditor): clean up tests that emit console.error

[joshblack]

Background: #2461

This PR updates MarkdownEditor tests that emit console.error(). Generally, these fell along the lines of addressing one of the following errors:

 ● Console
console.error
Warning: You seem to have overlapping act() calls, this is not supported. Be sure to await previous act() calls before making a new one.
at printWarning (node_modules/react-dom/cjs/react-dom-test-utils.development.js:67:30)
at error (node_modules/react-dom/cjs/react-dom-test-utils.development.js:43:5)
at onDone (node_modules/react-dom/cjs/react-dom-test-utils.development.js:1034:9)
at node_modules/react-dom/cjs/react-dom-test-utils.development.js:1073:13
console.error
Error: Not implemented: navigation (except hash changes)
at module.exports (/Users/joshblack/gh/primer/react/node_modules/jsdom/lib/jsdom/browser/not-implemented.js:9:17)
at navigateFetch (/Users/joshblack/gh/primer/react/node_modules/jsdom/lib/jsdom/living/window/navigation.js:77:3)
at exports.navigate (/Users/joshblack/gh/primer/react/node_modules/jsdom/lib/jsdom/living/window/navigation.js:55:3)
at Timeout._onTimeout (/Users/joshblack/gh/primer/react/node_modules/jsdom/lib/jsdom/living/nodes/HTMLHyperlinkElementUtils-impl.js:81:7)
at listOnTimeout (node:internal/timers:559:17)
at processTimers (node:internal/timers:502:7) {
type: 'not implemented'
}
at VirtualConsole.<anonymous> (node_modules/jest-environment-jsdom/build/index.js:60:23)
at module.exports (node_modules/jsdom/lib/jsdom/browser/not-implemented.js:12:26)
at navigateFetch (node_modules/jsdom/lib/jsdom/living/window/navigation.js:77:3)
at exports.navigate (node_modules/jsdom/lib/jsdom/living/window/navigation.js:55:3)
at Timeout._onTimeout (node_modules/jsdom/lib/jsdom/living/nodes/HTMLHyperlinkElementUtils-impl.js:81:7)

Often, the act() related violations were due to a Promise that had not resolved in an act().

[changeset-bot]

⚠️ No Changeset found

Latest commit: b9c1399

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[github-actions]

size-limit report 📦

Path	Size
dist/browser.esm.js	78.9 KB (0%)
dist/browser.umd.js	79.54 KB (0%)

[joshblack]

@siddharthkp quick bump when you get the chance to review!

[siddharthkp]

LGTM!