Update react monorepo to v19 (major) (#28914)

* Update react monorepo to v19

* Import JSX explicitly for React 19 compatibility

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update usages of refs for React 19 compatibility

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update react imports

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* Avoid legacy contexts as much as possible

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Avoid deprecated React symbols

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* Stash

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* Update usages of refs for React 19 compatibility

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Switch pillify to use a html-react-parser approach rather than DOM muddling

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate react html parsing

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate react html parsing

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate html parsing

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Memoize the EventContentBody component

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate html parsing

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

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* Iterate

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* Simplify

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* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Discard changes to src/Linkify.tsx

* Discard changes to src/components/views/messages/TextualBody.tsx

* Discard changes to src/settings/handlers/AbstractLocalStorageSettingsHandler.ts

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Prepare for React 19 upgrade

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Iterate

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* Remove stale comment

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---------

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

test/unit-tests/components/views/right_panel/UserInfo-test.tsx

@@ -467,7 +467,7 @@ describe("<UserInfo />", () => {
 
             await expect(screen.findByRole("button", { name: "Deactivate user" })).resolves.toBeInTheDocument();
             if (screen.queryAllByRole("progressbar").length) {
-                await waitForElementToBeRemoved(() => screen.queryAllByRole("progressbar"));
+                await act(() => waitForElementToBeRemoved(() => screen.queryAllByRole("progressbar")));
             }
             expect(container).toMatchSnapshot();
         });