Fix React hydration issues (#32958)

* Add more playwright axe tests to settings dialogs

* Add utility to jest setupTests to detect React hydration errors

* Iterate jest utility

* Fix axe issue heading-order

* Fix div-in-p issues

* Fix setupTests.ts

* Fix heading order

* Make types happier

* Fix hydration issues of thead containing text nodes

* Update tests

* Fix form-in-form React hydration issues

* Fix li-in-li React hydration issues

* Fix checked in form without onChange React hydration issue

* Fix styling bleeding from _common.pcss

* Update snapshots

* Fix more remaining issues

* Remove _common.pcss h2 rule altogether

* Fix test

* Update snapshots

* Iterate

* Iterate

* Update snapshots

* Simplify diff

* Test

* Update screenshots

* Update screenshot

apps/web/test/setupTests.ts

@@ -66,3 +66,28 @@ if (env["GITHUB_ACTIONS"] !== undefined) {
 require("./setup/setupManualMocks"); // must be first
 require("./setup/setupLanguage");
 require("./setup/setupConfig");
+
+// Utility to check for React errors during the tests
+// Fails tests on errors like the following:
+// In HTML, <div> cannot be a descendant of <p>.
+// In HTML, <form> cannot be a descendant of <form>.
+// In HTML, text nodes cannot be a child of <thead>.
+// This will cause a hydration error.
+// You provided a `checked` prop to a form field without an `onChange` handler.
+let errors: any[] = [];
+beforeEach(() => {
+    errors = [];
+    const originalError = console.error;
+    jest.spyOn(console, "error").mockImplementation((...args) => {
+        if (/validateDOMNesting|Hydration failed|hydration error|prop to a form field without an/i.test(args[0])) {
+            errors.push(args[0]);
+        }
+        originalError.call(console, ...args);
+    });
+});
+afterEach(() => {
+    mocked(console.error).mockRestore?.();
+    if (errors.length > 0) {
+        throw new Error("Test failed due to React hydration errors in the console.");
+    }
+});