fix: resolve xarray FacetGrid DeprecationWarning in plot_example.py

[sohampatil01-svg]

Describe your changes

Fixes a DeprecationWarning encountered during testing and plotting by replacing the deprecated g.axes attribute with g.axs on the xarray.plot.FacetGrid object in neural_lam/datastore/plot_example.py. This aligns the codebase with newer versions of xarray (>= 2022.11) which match matplotlib's plt.subplots standard.

No new dependencies are required.

Issue Link

closes #485

Type of change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📖 Documentation (Addition or improvements to documentation)

Checklist before requesting a review

• My branch is up-to-date with the target branch - if not update your fork with the changes from the target branch (use pull with --rebase option if possible).
• I have performed a self-review of my code
• For any new/modified functions/classes I have added docstrings that clearly describe its purpose, expected inputs and returned values
• I have placed in-line comments to clarify the intent of any hard-to-understand passages of my code
• I have updated the README to cover introduced code changes
• I have added tests that prove my fix is effective or that my feature works
• I have given the PR a name that clearly describes the change, written in imperative form (context).
• I have requested a reviewer and an assignee (assignee is responsible for merging). This applies only if you have write access to the repo, otherwise feel free to tag a maintainer to add a reviewer and assignee.

Checklist for reviewers

Each PR comes with its own improvements and flaws. The reviewer should check the following:

• the code is readable
• the code is well tested
• the code is documented (including return types and parameters)
• the code is easy to maintain

Author checklist after completed review

• I have added a line to the CHANGELOG describing this change, in a section
  reflecting type of change (add section where missing):
  • added: when you have added new functionality
  • changed: when default behaviour of the code has been changed
  • fixes: when your contribution fixes a bug
  • maintenance: when your contribution is relates to repo maintenance, e.g. CI/CD or documentation

Checklist for assignee

• PR is up to date with the base branch
• the tests pass
• (if the PR is not just maintenance/bugfix) the PR is assigned to the next milestone. If it is not, propose it for a future milestone.
• author has added an entry to the changelog (and designated the change as added, changed, fixed or maintenance)
• Once the PR is ready to be merged, squash commits and merge the PR.

[sadamov]

@sohampatil01-svg thanks, please create a corresponding issue, first. and also revert to the original PR template

[sohampatil01-svg]

@sohampatil01-svg thanks, please create a corresponding issue, first. and also revert to the original PR template

"Hi @sadamov , thank you for the feedback! I have now created a corresponding issue for this bug (#485) and updated the PR description using the project's original template. Please let me know if any further changes are needed."

[kshirajahere]

@sohampatil01-svg
You are still missing this part of PR template-->

## Checklist for reviewers

Each PR comes with its own improvements and flaws. The reviewer should check the following:
- [ ] the code is readable
- [ ] the code is well tested
- [ ] the code is documented (including return types and parameters)
- [ ] the code is easy to maintain

## Author checklist after completed review

- [ ] I have added a line to the CHANGELOG describing this change, in a section
  reflecting type of change (add section where missing):
  - *added*: when you have added new functionality
  - *changed*: when default behaviour of the code has been changed
  - *fixes*: when your contribution fixes a bug
  - *maintenance*: when your contribution is relates to repo maintenance, e.g. CI/CD or documentation

## Checklist for assignee

- [ ] PR is up to date with the base branch
- [ ] the tests pass
- [ ] (if the PR is not just maintenance/bugfix) the PR is assigned to the next milestone. If it is not, propose it for a future milestone.
- [ ] author has added an entry to the changelog (and designated the change as *added*, *changed*, *fixed* or *maintenance*)
- Once the PR is ready to be merged, squash commits and merge the PR.

[sohampatil01-svg]

"Thank you for the catch, @kshirajahere! I have now updated the PR body to include the missing sections and matched the exact formatting of the template. Please let me know if everything looks correct now."