Chore: Update typescript to v4.2.4 (#33297)

* Update typescript to v4.2.4

* Update @types/slate

* Fix QueryVariableEditor.test.tsx

* Fix search-related type errors

* Fix Plugin pages type errors

* Fix missing initializer errors

* Update snapshot

* Revert tsconfig changes

package.json

@@ -197,7 +197,7 @@
     "ts-jest": "26.4.4",
     "ts-node": "9.0.0",
     "tslib": "2.1.0",
-    "typescript": "4.1.2",
+    "typescript": "4.2.4",
     "webpack": "4.41.5",
     "webpack-bundle-analyzer": "3.6.0",
     "webpack-cleanup-plugin": "0.5.1",