Include ancillary variables and cell_measures during intersect

[ESadek-MO]

🚀 Pull Request

Closes #5413.

To do:

• [x] Add rough functionality
• [x] Refactor functions into one consolidated
• [ ] Add tests

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 91.30435% with 2 lines in your changes missing coverage. Please review.

Project coverage is 89.77%. Comparing base (b8f554f) to head (2787ca5). Report is 1 commits behind head on main.

Files	Patch %	Lines
lib/iris/cube.py	91.30%	1 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5804      +/-   ##
==========================================
- Coverage   89.77%   89.77%   -0.01%     
==========================================
  Files          88       88              
  Lines       23026    23037      +11     
  Branches     5036     5038       +2     
==========================================
+ Hits        20672    20681       +9     
- Misses       1623     1624       +1     
- Partials      731      732       +1     

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[ESadek-MO]

Two notes on last commit:

• I decided against consolidating create_coord into create_metadata as it would require so many if checks and the like it would've been harder to read. That said, I'm happy to be vetoed on this.
• This PR threw up some flake8 errors from previous changes; cube was being used as a variable despite being imported as well. All these instances have been changed to c instead

[pp-mo]

Hi @ESadek-MO FYI I just assigned this to you.. I was reviewing my Peloton tasks, and this popped up, but being in Draft I think it is still on you.