Fix code bug that causes missing f006 APCP

[BoCui-NOAA]

Description

This PR is to fix a bug in code ensstat.f90 that causes f006 APCP filed missing in output files. The code previously had a line to identify two APCP variables in AIGEFS. Since both AIGEFS and GEFS no longer output the total APCP, this line are removed to prevent missing data.

Type of change

• Maintenance (code refactor, clean-up, new CI test, etc.)

Change characteristics

• Is this a breaking change (a change in existing functionality)? NO
• Does this change require a documentation update? NO

How has this been tested?

• Cycled test on WCOSS2

Checklist

• Any dependent changes have been merged and published
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• New and existing tests pass with my changes
• I have made corresponding changes to the documentation if necessary