Refactor composition layout manager.

[has2k1]

Reduced the places where we do recursion.

[codecov]

Codecov Report

❌ Patch coverage is 95.52239% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.71%. Comparing base (e1e58ac) to head (84e6988).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
plotnine/_mpl/layout_manager/_layout_tree.py	95.52%	3 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #978      +/-   ##
==========================================
+ Coverage   86.61%   86.71%   +0.09%     
==========================================
  Files         194      194              
  Lines       13362    13109     -253     
  Branches     1646     1598      -48     
==========================================
- Hits        11574    11367     -207     
+ Misses       1239     1205      -34     
+ Partials      549      537      -12     

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