refactor: some string-related code cleanup/refactor

[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:

Issue

If applicable, what issue does this address?

Closes: #

Testing

If relevant, please state how this was tested. All changes must be tested to work:

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

• Windows
• macOS
• Linux

Checklist

If relevant, ensure the following have been met:

• 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 83.10185% with 73 lines in your changes are missing coverage. Please review.

Project coverage is 55.93%. Comparing base (bcc8917) to head (4fac790).

Files	Patch %	Lines
src/utils/strings.rs	93.72%	18 Missing ⚠️
src/widgets/process_table/proc_widget_data.rs	40.00%	12 Missing ⚠️
src/utils/data_prefixes.rs	65.62%	11 Missing ⚠️
src/widgets/disk_table.rs	50.00%	10 Missing ⚠️
src/widgets/process_table/sort_table.rs	0.00%	8 Missing ⚠️
src/widgets/temperature_table.rs	14.28%	6 Missing ⚠️
src/data_conversion.rs	89.65%	3 Missing ⚠️
src/lib.rs	60.00%	2 Missing ⚠️
src/canvas/components/data_table.rs	0.00%	1 Missing ⚠️
src/canvas/components/data_table/sortable.rs	0.00%	1 Missing ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1463      +/-   ##
==========================================
+ Coverage   55.84%   55.93%   +0.09%     
==========================================
  Files          97       99       +2     
  Lines       18190    18191       +1     
==========================================
+ Hits        10159    10176      +17     
+ Misses       8031     8015      -16     

Flag	Coverage Δ
macos-12	39.31% <65.27%> (-0.01%)	⬇️
ubuntu-latest	58.54% <83.10%> (+0.09%)	⬆️
windows-2019	39.49% <65.73%> (-0.01%)	⬇️

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