Fix invalid tree style changes

[humdrum]

What this PR does / why we need it:

• Fix invalid tree style changes yorkie-js-sdk#804

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Additional documentation:

Checklist:

• Added relevant tests or not required
• Didn't break anything

[codecov]

Codecov Report

Attention: Patch coverage is 10.34483% with 52 lines in your changes are missing coverage. Please review.

Project coverage is 40.68%. Comparing base (4b063d8) to head (3a78fd1).

Files	Patch %	Lines
Tests/Integration/TreeIntegrationTests.swift	0.00%	34 Missing ⚠️
Sources/Document/CRDT/CRDTTree.swift	0.00%	17 Missing ⚠️
Sources/Document/CRDT/RHT.swift	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #167      +/-   ##
==========================================
- Coverage   40.76%   40.68%   -0.08%     
==========================================
  Files         104      104              
  Lines       18024    18062      +38     
==========================================
+ Hits         7347     7349       +2     
- Misses      10677    10713      +36     

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