feature add to INR making grid and ptycho viz

[arthurmccray]

What does this PR do?

This adds an option to the make_equispaced_grid method of Siren like networks to handle num_points as an option instead of sampling. It's a simple feature add that was in my ptycho-inr branch but as that is no longer being actively worked on, I wanted to add the feature to dev.

It also adds a couple quality-of-life updates to the iterative ptycho visualizations, but nothing that changes normal behavior.

What should the reviewer(s) do?

see if it makes sense, merge if so.

• This PR introduces a public-facing change (e.g., API, CLI input/output).
• Documentation (e.g., tutorials, examples, README) has been updated

Reviewer checklist

• Tests pass and are appropriate for the changes
• Documentation and examples are sufficient and clear
• Imported or adapted code has a compatible license
• The implementation matches the stated intent of the contribution

[cedriclim1]

lgtm