other: use f32 for process percentage values

[ClementTsang]

This cuts down memory by a tiny bit, and we don't need a full f64 for percentage values.

Description

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Issue

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Closes: #

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

Patch coverage: 6.66% and project coverage change: -0.02 ⚠️

Comparison is base (9cd953e) 31.61% compared to head (a3c6982) 31.59%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1212      +/-   ##
==========================================
- Coverage   31.61%   31.59%   -0.02%     
==========================================
  Files          97       97              
  Lines       16502    16510       +8     
==========================================
  Hits         5217     5217              
- Misses      11285    11293       +8     

Flag	Coverage Δ
macos-12	33.17% <12.50%> (-0.02%)	⬇️
ubuntu-latest	33.17% <7.14%> (-0.02%)	⬇️
windows-2019	33.42% <14.28%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/app/data_harvester/processes.rs	0.00% <ø> (ø)
src/app/data_harvester/processes/linux.rs	16.72% <0.00%> (-0.18%)	⬇️
...c/app/data_harvester/processes/unix/process_ext.rs	0.00% <0.00%> (ø)
src/app/data_harvester/processes/windows.rs	0.00% <ø> (ø)
src/app/frozen_state.rs	15.78% <ø> (ø)
src/app/query.rs	0.00% <0.00%> (ø)
src/widgets/process_table/proc_widget_data.rs	36.32% <ø> (ø)
src/clap.rs	100.00% <100.00%> (ø)

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