Fix UDF checkpoint logic

[acquamarin]

When initializing the write version of the catalogContent, we simply create a new catalogContent and regenerate the built-in funcionts. However, this discards all UDFs since all functions are not copied.
This PR correctly copies all functions when initializing the write version of the catalogContent

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (295d2de) 91.38% compared to head (57784b1) 91.40%.

Files	Patch %	Lines
src/function/built_in_functions.cpp	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2451      +/-   ##
==========================================
+ Coverage   91.38%   91.40%   +0.01%     
==========================================
  Files        1023     1023              
  Lines       37235    37246      +11     
==========================================
+ Hits        34028    34044      +16     
+ Misses       3207     3202       -5     

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[ray6080]

Better give a more descriptive title or add a brief description, as the title doesn't seem to cover the problem of functions with transaction.