Convert resolver errors to warnings

[kddejong]

Issue #, if available:

Description of changes:

• Convert resolver errors to warnings

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[codecov]

Codecov Report

Attention: Patch coverage is 98.68421% with 1 line in your changes missing coverage. Please review.

Project coverage is 93.41%. Comparing base (83b0cdb) to head (baf5776).
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/cfnlint/rules/functions/_BaseFn.py	87.50%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3493      +/-   ##
==========================================
+ Coverage   93.39%   93.41%   +0.02%     
==========================================
  Files         328      336       +8     
  Lines       11119    11184      +65     
  Branches     2324     2328       +4     
==========================================
+ Hits        10385    10448      +63     
  Misses        411      411              
- Partials      323      325       +2     

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