Support v1 recipes in CrossRBaseMigrator

[mgorny]

Description:

Add support for v1 recipes in CrossRBaseMigrator. Here the logic
made it easy to output a single combined condition:

    - if: build_platform != target_platform
      then:
        - cross-r-base ${{ r_base }}
        - r-rlang

Checklist:

• Pydantic model updated or no update needed

Cross-refs, links to issues, etc:

Part of bug #3642

[mgorny]

FWICS we could just append all the lines as a single element here, but I've figured out that since it's a list of lines by design, it's cleaner to add them separately.

[codecov]

Codecov Report

Attention: Patch coverage is 95.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 76.98%. Comparing base (277fe85) to head (f2059b5).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
conda_forge_tick/migrators/cross_compile.py	93.75%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3836      +/-   ##
==========================================
- Coverage   78.38%   76.98%   -1.40%     
==========================================
  Files         138      138              
  Lines       15194    15204      +10     
==========================================
- Hits        11910    11705     -205     
- Misses       3284     3499     +215     

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[beckermr]

I think we want the flaky decorator inside the pytest parameterize decorator again.

[mgorny]

I think we want the flaky decorator inside the pytest parameterize decorator again.

Sorry about that. Remember about it for Python, failed to remember here.

[beckermr]

We can merge this despite the target_platform versus host_platform issue since we'll need to change that everywhere including rattler later, and this won't happen for a while.

Is that OK @isuruf?