chore:(deps): bump @types/react-dom from 16.9.8 to 16.9.9 in /explorer (#13228)

Bumps [@types/react-dom](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react-dom) from 16.9.8 to 16.9.9.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/react-dom)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

explorer/package-lock.json

@@ -4200,9 +4200,9 @@
       }
     },
     "@types/react-dom": {
-      "version": "16.9.8",
-      "resolved": "https://registry.npmjs.org/@types/react-dom/-/react-dom-16.9.8.tgz",
-      "integrity": "sha512-ykkPQ+5nFknnlU6lDd947WbQ6TE3NNzbQAkInC2EKY1qeYdTKp7onFusmYZb+ityzx2YviqT6BXSu+LyWWJwcA==",
+      "version": "16.9.9",
+      "resolved": "https://registry.npmjs.org/@types/react-dom/-/react-dom-16.9.9.tgz",
+      "integrity": "sha512-jE16FNWO3Logq/Lf+yvEAjKzhpST/Eac8EMd1i4dgZdMczfgqC8EjpxwNgEe3SExHYLliabXDh9DEhhqnlXJhg==",
       "requires": {
         "@types/react": "*"
       }

explorer/package.json

@@ -17,7 +17,7 @@
     "@types/jest": "^26.0.15",
     "@types/node": "^14.14.6",
     "@types/react": "^16.9.53",
-    "@types/react-dom": "^16.9.8",
+    "@types/react-dom": "^16.9.9",
     "@types/react-router-dom": "^5.1.6",
     "@types/react-select": "^3.0.22",
     "@types/socket.io-client": "^1.4.34",