docs(examples): strip committed notebook outputs to match convention

The migrated notebooks were committed with re-executed outputs, but this project keeps notebooks output-free and lets nbsphinx execute them at docs-build time (as the other Hydroshare notebooks do). Strip the outputs and the machine-specific language_info.version.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: thodson-usgs