fix(app): Set snapshotTag value for FileDisplay on snapshots

[nellh]

Fixes an issue where the FileDisplay component would not use the snapshot version in the URL for loading a file.

Previously the 1.0.1 snapshot would try to load a file like this:
https://openneuro.org/crn/datasets/ds001033/files/sub-02:anat:sub-02_T1w.nii.gz

Correct URL looks like this:
https://openneuro.org/crn/datasets/ds001033/snapshots/1.0.1/files/sub-02:anat:sub-02_T1w.nii.gz

This is a regression caused by the React Router V6 updates.

[codecov]

Codecov Report

Merging #2723 (3cff04d) into master (458a60d) will decrease coverage by 0.00%.
The diff coverage is 63.15%.

@@            Coverage Diff             @@
##           master    #2723      +/-   ##
==========================================
- Coverage   76.01%   76.01%   -0.01%     
==========================================
  Files         409      409              
  Lines       66856    66872      +16     
  Branches     2039     2037       -2     
==========================================
+ Hits        50820    50830      +10     
- Misses      15985    15991       +6     
  Partials       51       51              

Impacted Files	Coverage Δ
...uro-app/src/scripts/dataset/files/file-display.jsx	49.00% <46.15%> (-0.44%)	⬇️
...src/scripts/dataset/routes/tab-routes-snapshot.tsx	100.00% <100.00%> (ø)

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