use sample meshes for examples

[bjlittle]

🚀 Pull Request

Description

This pull-request simplifies the extraction.wedge_manifold, warp.from_unstructured__lfric_orog and warp.from_unstructured__lfric_orog_eqc examples by using the convenience of the runtime generated geovista.pantry.meshes rather than loading the associated geovista.pantry.data to construct the relevant meshes.

The focus of those examples is not to highlight the capabilities of the geovista.bridge; there are several other dedicated examples that do that.

As a result, the examples have less connective tissue code to distract the reader, and also make use of the sample rather than the load sphinx-tag category.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.61%. Comparing base (d63f59a) to head (92705f6).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1339      +/-   ##
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- Coverage   91.61%   91.61%   -0.01%     
==========================================
  Files          60       60              
  Lines        3031     3028       -3     
==========================================
- Hits         2777     2774       -3     
  Misses        254      254              

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