Add authorization to AuthenticatedFileHandler

[jiajunjie]

https://github.com/jupyter-server/jupyter_server/blob/31cdf4db3ea352666de5bcce430ddde3ba79f882/docs/source/operators/security.rst#L251-L255 /files requests are handled by AuthenticatedFileHandler by default.

[codecov-commenter]

Codecov Report

Base: 76.28% // Head: 75.44% // Decreases project coverage by -0.84% :warning:

Coverage data is based on head (e9b0831) compared to base (e66306d). Patch coverage: 75.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1021      +/-   ##
==========================================
- Coverage   76.28%   75.44%   -0.85%     
==========================================
  Files          63       63              
  Lines        8228     8235       +7     
  Branches     1637     1642       +5     
==========================================
- Hits         6277     6213      -64     
- Misses       1546     1618      +72     
+ Partials      405      404       -1     

Impacted Files	Coverage Δ
jupyter_server/auth/authorizer.py	84.61% <50.00%> (-15.39%)	:arrow_down:
jupyter_server/base/handlers.py	66.98% <100.00%> (+0.25%)	:arrow_up:
jupyter_server/nbconvert/handlers.py	29.09% <0.00%> (-50.00%)	:arrow_down:
jupyter_server/_tz.py	94.11% <0.00%> (-5.89%)	:arrow_down:
jupyter_server/services/contents/filemanager.py	73.00% <0.00%> (-1.56%)	:arrow_down:
jupyter_server/services/kernels/handlers.py	61.61% <0.00%> (-1.02%)	:arrow_down:

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[jiajunjie]

@blink1073 Please take a look. /files requests handled by AuthenticatedFileHandler are not authorized. I suggest adding the authorization.

[Zsailer]

Thanks, @jiajunjie. This LGTM!

[welcome[bot]]

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