feat: Allow reshaping empty array to Array dtype

[hexane360]

Changes reshape logic to allow reshaping to a Series with Array dtype of length 0. Zero width arrays are still unsupported.

This is a rough draft, please let me know what you think.

Examples:

  pl.Series([]).reshape((0, 2)) => shape(0, 2) (used to error)
  pl.Series([]).reshape((-1, 2, 3)) => shape (0, 2, 3) (used to error)
  pl.Series([]).reshape((0, 0)) => InvalidOperationError("cannot reshape array into shape containing a zero dimension after the first")
  pl.Series([]).reshape((5, -1)) => InvalidOperationError("cannot reshape empty array into shape (5, -1)")

Some error messages are changed. Does polars consider that a breaking change? For instance, pl.Series([]).reshape((0, 0)) used to error with the message "cannot reshape empty array into shape (0, 0)".

Fixes #18369

[hexane360]

Another issue this may fix: #18598

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 79.86%. Comparing base (71a8b05) to head (47d670c).
Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-core/src/series/ops/reshape.rs	93.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18876      +/-   ##
==========================================
- Coverage   79.88%   79.86%   -0.02%     
==========================================
  Files        1522     1522              
  Lines      206958   206955       -3     
  Branches     2906     2906              
==========================================
- Hits       165322   165294      -28     
- Misses      41088    41113      +25     
  Partials      548      548              

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[hexane360]

Rebased against main

[coastalwhite]

This is now done by #18940