chore: Update examples for poetry to uv migration

[BulkBeing]

The PR for migrating to uv introduced a bug in building images.

Also updates sink examples which were using older builtin map in pipeline spec.

Tested by building a few images and running them within a Numaflow pipeline.

Also tested by initializing a new project and installing package from current main:

uv add "pynumaflow @ git+https://github.com/numaproj/numaflow-python.git@febbe7a3ff5c601e5263b1276ff18a41a6a1c0c2#subdirectory=packages/pynumaflow"

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.31%. Comparing base (febbe7a) to head (4ca1697).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #336      +/-   ##
==========================================
+ Coverage   94.15%   94.31%   +0.15%     
==========================================
  Files          67       67              
  Lines        3182     3182              
  Branches      179      179              
==========================================
+ Hits         2996     3001       +5     
+ Misses        151      146       -5     
  Partials       35       35              

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