fix: file info bugs

[KristinAoki]

JIRA Ticket: TNL-10953

This PR makes addresses the following ui bugs in the file info modal:

1. Makes the file preview a fixed height and width
2. Adjusts the date added to use the localized version of the time instead of utc

[codecov]

Codecov Report

Patch coverage: 85.71% and project coverage change: +0.01% 🎉

Comparison is base (b65f4f2) 84.38% compared to head (e215835) 84.40%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #571      +/-   ##
==========================================
+ Coverage   84.38%   84.40%   +0.01%     
==========================================
  Files         259      259              
  Lines        4247     4252       +5     
  Branches      959      959              
==========================================
+ Hits         3584     3589       +5     
  Misses        639      639              
  Partials       24       24              

Files Changed	Coverage Δ
src/files-and-uploads/FileThumbnail.jsx	77.77% <50.00%> (ø)
src/files-and-uploads/FileInfo.jsx	83.33% <100.00%> (+1.51%)	⬆️
src/files-and-uploads/data/utils.js	100.00% <100.00%> (ø)

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