Fix: Content Classification: Make character count locale-aware

[hbhalodia]

What?

Closes #571

Why?

• PR updates the content clasification experiment for suggestion to use dynamic wordCount based on user's locale.
• It uses words, characters_excluding_spaces, or characters_including_spaces for wordCount.

How?

• Updates the useContentClassification to use wordCountType as suggested here and most of places, https://github.com/WordPress/gutenberg/blob/1ecc3d2fe9c819af35ef312563805bc16a103036/packages/block-library/src/post-time-to-read/edit.js#L51-L61

Use of AI Tools

• None

Testing Instructions

• Change the site language to Japanese.
• Open a post.
• Copy the following Japanese text multiple times to create content: こんにちは。
• Confirm that the Suggest Categories button should enable now.

Screenshots or screencast

Before	After

Changelog Entry

Added - Determine wordCountType for content classification experiment to use words or characters based on users locale.

[github-actions]

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Co-authored-by: hbhalodia <hbhalodia@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>
Co-authored-by: dkotter <dkotter@git.wordpress.org>

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.41%. Comparing base (396fcc3) to head (e0c4bb4).

Additional details and impacted files

@@            Coverage Diff             @@
##             develop     #577   +/-   ##
==========================================
  Coverage      71.41%   71.41%           
  Complexity      1158     1158           
==========================================
  Files             67       67           
  Lines           5584     5584           
==========================================
  Hits            3988     3988           
  Misses          1596     1596           

Flag	Coverage Δ
unit	71.41% <ø> (ø)

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[dkotter]

Code looks good here but see my comment here. Thinking we may want to hold this pending that discussion as I'd love to be more consistent with how we handle this across the plugin.

[hbhalodia]

I am closing this PR.

We can improve same in the PR - #581