Fixing the hidden code and figure cells in the Euclid q1 hats magntitude webpage

[DeekshaMohanty]

Summary

This PR fixes the hidden code and figure cells in the Euclid Q1 HATS magnitudes tutorial page.

The figure outputs were being placed inside cells using hide-cell, which caused both the code and output figure to be hidden by default. These have been changed to hide-input so that only the figure output is displayed.

This issue was left over from #335.

Related issue

Closes #361.

Testing procedure

• Created an environment using tutorial_requirements.txt and site_requirements.txt.
• Built the documentation locally with Jupyter Book using the execution and strict-build options.
• Served the generated HTML locally and verified that the figure is displayed and the code remains hidden.

[troyraen]

Looks good. Thank you!

[troyraen]

@DeekshaMohanty go ahead and merge this. It will trigger a deployment job on GHA (I think it's called "Build and Publish HTML"). Go to the Actions tab for this repo and keep an eye on that job. If it succeeds it will probably take between 10-30 minutes. If it takes much longer than that it likely means it's stuck. If it does that, or if it fails, let me know and we'll take a look at it together to see what went wrong.