Fallback to filepath if grid_media_field is undefined for the current view

[manivoxel51]

(Please fill in changes proposed in this fix)

• fix
• unittest

to reproduce

• Follow https://docs.voxel51.com/user_guide/app.html#multiple-media-fields
• pick thumbnail_path in grid settings
• use the Patcher component to create toPatches dataset

Screen.Recording.2023-09-08.at.2.00.56.PM.mov

After fix

Screen.Recording.2023-09-08.at.2.00.21.PM.mov

huge thanks to Ben for help! 🍨

Unit test

Screen.Recording.2023-09-08.at.2.47.52.PM.mov

(Details)

Release Notes

Is this a user-facing change that should be mentioned in the release notes?

• No. You can skip the rest of this section.
• Yes. Give a description of this change to be included in the release
  notes for FiftyOne users.

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if this PR is part of a larger change.)

What areas of FiftyOne does this PR affect?

• App: FiftyOne application changes
• Build: Build and test infrastructure changes
• Core: Core fiftyone Python library changes
• Documentation: FiftyOne documentation changes
• Other

[codecov]

Codecov Report

Patch coverage: 81.81% and project coverage change: +0.01% 🎉

Comparison is base (ee93587) 15.98% compared to head (c1992bb) 16.00%.
Report is 2 commits behind head on release/v0.22.0.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           release/v0.22.0    #3498      +/-   ##
===================================================
+ Coverage            15.98%   16.00%   +0.01%     
===================================================
  Files                  573      573              
  Lines                71309    71326      +17     
  Branches               800      804       +4     
===================================================
+ Hits                 11401    11417      +16     
- Misses               59908    59909       +1     

Flag	Coverage Δ
app	16.00% <81.81%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
app/packages/state/src/hooks/useStateUpdate.ts	25.67% <33.33%> (ø)
app/packages/state/src/recoil/options.ts	98.31% <89.47%> (-1.69%)	⬇️

... and 1 file with indirect coverage changes

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[benjaminpkane]

LGTM! Creating unit tests for these is a good call. I tweaked the implementation a little to use fieldPaths instead of the schema directly. This simplified mock data and makes the assertions more self-contained.