test(charm): clean up and consolidate charm tests

[srtaalej]

Changelog

Removes redundant tests and consolidates scattered test functions into table-driven tests in the
style package.

Summary

Follow-up to #365 (charm-lipgloss-migration). That PR added new charm/lipgloss tests alongside existing aurora tests, resulting in some redundancy and inconsistent test patterns. This PR cleans that up.

Removed redundant tests:

• TestEmojiEmpty — subset of TestEmoji (empty-string case folded in)
• TestRender — render() is already exercised by all 16 testStyleFunc calls
• Test_styleExampleLine — internal helper already covered by Test_ExampleTemplatef_Charm
• TestStyleFlags_CharmDisabled — folded into TestStyleFlags as a table case

Consolidated into table-tests:

• TestGetKeyLengthZero/Matched/Long/First (4 funcs → 1)
• TestSectionfEmpty/Header/EmptyEmoji (3 funcs → 1)
• TestSectionSecondaryfEmpty/Plain/Format/Indent (4 funcs → 1)
• TestCommandfPrimary/Secondary (2 funcs → 1)

Test steps

make test testdir=internal/style
make lint

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.48%. Comparing base (755ccfe) to head (3aa6640).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #390   +/-   ##
=======================================
  Coverage   65.47%   65.48%           
=======================================
  Files         218      218           
  Lines       18120    18120           
=======================================
+ Hits        11864    11865    +1     
- Misses       5161     5162    +1     
+ Partials     1095     1093    -2     

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[zimeg]

@srtaalej Nice though let's hope to keep tests with code changes onward 🚢 💨