Add missing typing to NWBConverter backend and backend options

[h-mayorquin]

Running local tests for the next release I noticed and changed three things:

1. The converter was missing the zarr option in the signature for typing. I added the typing and modified the docstring accordingly.
2. The miniscope tests were comparing session start time with time zone included. This only works on the CI but fails locally if someone is not in the time zone of the CI server. I made the comparison on the naive datetime object only.
3. The TDT interface for fiber photometry is outputting files on the repo directory. I changed the conversion gallery so it uses the same machinery as all the other interfaces (where the output of the gallery is written to a temporary directory).

[weiglszonja]

Great catch, I didn't think about that this can cause issues. Thanks!

[weiglszonja]

Looks good, one small typo. Thanks!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.75%. Comparing base (96dfdff) to head (4dd1cd6).
Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1160      +/-   ##
==========================================
+ Coverage   90.69%   90.75%   +0.06%     
==========================================
  Files         129      129              
  Lines        8189     8286      +97     
==========================================
+ Hits         7427     7520      +93     
- Misses        762      766       +4     

Flag	Coverage Δ
unittests	90.75% <ø> (+0.06%)	⬆️

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Files with missing lines	Coverage Δ
src/neuroconv/nwbconverter.py	94.96% <ø> (ø)

... and 3 files with indirect coverage changes