feat(python): Allow column expressions in DataFrame unnest

[alexander-beedie]

Closes #20128.

We can redirect to LazyFrame to handle this consistently, dropping the passthrough method on PyDataFrame.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.64%. Comparing base (24fccc4) to head (fb79ea2).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #20846      +/-   ##
==========================================
- Coverage   79.64%   79.64%   -0.01%     
==========================================
  Files        1571     1571              
  Lines      223156   223149       -7     
  Branches     2546     2546              
==========================================
- Hits       177731   177721      -10     
- Misses      44841    44844       +3     
  Partials      584      584              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ritchie46]

Yeap, can we add a simple test to verify we the experssions work.

[alexander-beedie]

Yeap, can we add a simple test to verify we the experssions work.

Ooof... shame on me; done ✌️