Clear vegetation during transition to rangeland

[JessicaNeedham]

Description:

This PR changes the land use logic ruleset so that vegetation is cleared when land use classes change from primary or secondary land to rangeland. This results in better alignment with global veg C products.

Collaborators:

@kjetilaas @rosiealice

Expectation of Answer Changes:

This should not be answer changing in simulations with steady state land use (i.e. spin ups or 2000s runs). It will change answers in historic runs with time series of land use change. It will result in less vegetation in rangeland areas.

Checklist:

• My change requires a change to the documentation.
• I have updated the in-code documentation .AND. (the technical note .OR. the wiki) accordingly.
• I have read the CONTRIBUTING document.
• FATES PASS/FAIL regression tests were run
• If answers were expected to change, evaluation was performed and provided

Test Results:

Not tested with the most recent tag. Previous runs from sci.1.85.1_api.40.0.0_nor_sci2_api1 comparing to the default are here:

With clearing (this PR):

Without clearing (current default):