Upgrade to React 16.14

[maddiedierker]

Upgrades React from 15.4 to 16.14, along with some supplementary changes and test fixes. Tracked as XTEAM-362.

Depends on #42168. Reapplies the changes in #42157, which were reverted in #42165. I merged the original PR in order to confirm which UI/eyes tests would fail on the test environment. Those failures are logged here. (Note: there were actually less eyes test failures when we deployed this change because I ended up splitting the redux/react-redux into a separate PR.)

We had each cabal bug bash to smoke test their parts of the product. Results here.

Description of each commit in this change

• d7e99b8 + 5f33aa8 - Upgrades react, react-dom, and our enzyme adapter. Updates imports for the enzyme adapter. Removes react-addons-test-utils, which is replaced by react-dom/test-utils.
• 9fff4be - Temporarily allows warnings for LessonProgress.story.jsx, which will no longer be needed once react-tooltip has been upgraded. (cc @Erin007)
• 78fbc1e - Allows warnings in unit, integration, and storybook tests. All warnings are due to deprecated lifecycle methods (either from our code or our dependencies). See more in "Follow-up work."
• ab433a8 - Disables UI tests on mobile Safari due to this issue. Similar to the change made in Upgrade react 15.6 #32063, which was later reverted.
• Filter for 3 commits - Fixes a bug I created in this commit. More on the bug here.

Follow-up work

• XTEAM-377 - Run a codemod to get rename deprecated lifecycle methods in our code to be prepended with "UNSAFE_". This gets rid of many warnings while we're refactoring those methods away.
• XTEAM-378 - Upgrade react-tooltip. Fixes the warning in LessonProgress.story.jsx.
• XTEAM-375 - Upgrade react-inspector. Gets rid of deprecation warnings in some tests, but requires updates to a few tests, so should be separate from this upgrade.
• XTEAM-376 - Upgrade redux & react-redux. Gets rid of deprecation warnings in some tests, but requires some code and test changes, so should be separate from this upgrade.
• XTEAM-379 - Re-allow test failures for warnings (depends on codemod changes and dependency upgrades).
• XTEAM-328 (v2 upgrade) / XTEAM-364 (v4 upgrade) - Upgrade react-select (from ^1.2.1 to ~4). This is a large change as the API has changed significantly between versions, and this package is used in various places throughout our codebase. This isn't likely to happen right after this upgrade.

[Erin007]

Thanks for the through documentation in the PR description and code TODOs! This will make follow up sooo much easier.

[Erin007]

🎉

[jmkulwik]

This is awesome! I'm so excited & happy to see this coming together!

[jmkulwik]

One tiny NIT: In the description, you have this line

Upgrade react-select to v2 and v4, respectively.

Is there a second thing that should be upgraded? The wording seems to imply react-select and something else needs to be upgraded.

[maddiedierker]

One tiny NIT: In the description, you have this line

Upgrade react-select to v2 and v4, respectively.

Is there a second thing that should be upgraded? The wording seems to imply react-select and something else needs to be upgraded.

no, this means we need to upgrade react-select (currently at ^1.2.1) to version 4, but that it should happen in 2 steps (upgrade to v2 first then to v4) because of the large API changes. the "respectively" part is referring to the jira tasks -- XTEAM-328 is for the v2 upgrade, and XTEAM-364 is for v4. i'll update that bullet to clarify!