Bump @jupyterlab/observables from 4.5.3 to 5.3.2

Bumps [@jupyterlab/observables](https://github.com/jupyterlab/jupyterlab) from 4.5.3 to 5.3.2.
- [Release notes](https://github.com/jupyterlab/jupyterlab/releases)
- [Changelog](https://github.com/jupyterlab/jupyterlab/blob/main/CHANGELOG.md)
- [Commits](https://github.com/jupyterlab/jupyterlab/compare/@jupyterlab/[email protected]...@jupyterlab/[email protected])

---
updated-dependencies:
- dependency-name: "@jupyterlab/observables"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

packages/experiment-manager/package.json

@@ -38,7 +38,7 @@
         "@jupyterlab/application": "3.5.3",
         "@jupyterlab/coreutils": "5.5.3",
         "@jupyterlab/docregistry": "3.5.3",
-        "@jupyterlab/observables": "4.5.3",
+        "@jupyterlab/observables": "5.3.2",
         "@jupyterlab/services": "6.5.3",
         "@jupyterlab/launcher": "3.5.3",
         "@jupyterlab/mainmenu": "3.5.3",