other: show N/A for Nvidia GPUs if we detect one but can't get temps

[ClementTsang]

Description

A description of the change, what it does, and why it was made. If relevant (such as any change that modifies the UI), please provide screenshots of the changes:

Something that I noticed; if we do see GPUs but can't get the temp, it's probably fine to return N/A rather than no entry at all.

Issue

If applicable, what issue does this address?

Possibly related to #1554?

Testing

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If this is a code change, please also indicate which platforms were tested:

• Windows
• macOS
• Linux

Checklist

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• Areas your change affects have been linted using rustfmt (cargo fmt)
• The change has been tested and doesn't appear to cause any unintended breakage
• Documentation has been added/updated if needed (README.md, help menu, doc pages, etc.)
• The pull request passes the provided CI pipeline
• There are no merge conflicts
• If relevant, new tests were added (don't worry too much about coverage)

[codecov]

Codecov Report

Attention: Patch coverage is 58.53659% with 17 lines in your changes missing coverage. Please review.

Project coverage is 35.96%. Comparing base (c65121c) to head (199d95e).

Files	Patch %	Lines
src/data_collection/nvidia.rs	0.00%	8 Missing ⚠️
src/app/filter.rs	71.42%	6 Missing ⚠️
src/data_collection/network/sysinfo.rs	0.00%	1 Missing ⚠️
src/data_collection/temperature/sysinfo.rs	0.00%	1 Missing ⚠️
src/options.rs	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (c65121c) and HEAD (199d95e). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (c65121c)	HEAD (199d95e)
ubuntu-latest	1	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1557      +/-   ##
==========================================
- Coverage   41.41%   35.96%   -5.45%     
==========================================
  Files         114      108       -6     
  Lines       17847    16844    -1003     
==========================================
- Hits         7391     6058    -1333     
- Misses      10456    10786     +330     

Flag	Coverage Δ
macos-12	36.71% <58.53%> (-0.02%)	⬇️
ubuntu-latest	?
windows-2019	36.91% <58.53%> (-0.02%)	⬇️

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