chore: Simplify DEFAULT_CHAR_REGEX for tag editor

[avinashbot]

Description

https://caniuse.com/mdn-javascript_regular_expressions_unicode_character_class_escape

How has this been tested?

Relying on existing tests and maybe a quick dry run, but maybe a couple more tests won't hurt.

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (a086982) 94.75% compared to head (85cd305) 94.75%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1886      +/-   ##
==========================================
- Coverage   94.75%   94.75%   -0.01%     
==========================================
  Files         661      661              
  Lines       17989    17988       -1     
  Branches     5950     5950              
==========================================
- Hits        17045    17044       -1     
  Misses        879      879              
  Partials       65       65              

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