Bump @lumino/widgets from 2.7.1 to 2.7.2 in /js

Bumps [@lumino/widgets](https://github.com/jupyterlab/lumino) from 2.7.1 to 2.7.2.
- [Release notes](https://github.com/jupyterlab/lumino/releases)
- [Changelog](https://github.com/jupyterlab/lumino/blob/main/CHANGELOG.md)
- [Commits](https://github.com/jupyterlab/lumino/compare/@lumino/[email protected]...@lumino/[email protected])

---
updated-dependencies:
- dependency-name: "@lumino/widgets"
  dependency-version: 2.7.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]