Patch for MiRS v11r10, September 11, 2024.
Shuyan Liu, Shu-yan.liu@noaa.gov

fix the issue of: all AMSUA channels are bad, MHS channels has problems related to L1 calibration

This problem is seen in both MetopB and MetopC

Background: If some channels are bad or missing, MiRS turns off the channel and perform retrieval

Solution: if more than half of the AMSUA channels are bad, flagged as qc fail.

Codes: src/testbed/rdr2tdr/rdr2tdr_metopC_amsua.f90
                   src/testbed/rdr2tdr/rdr2tdr_metopB_amsua.f90
                   src/testbed/fm/ fm_metopC.f90
                   src/testbed/fm/ fm_metopB.f90

Note: this is a temporal solution under the condition that MHS are not correctly flagged in L1 
      and majority channels of the AMSUA data are missing. 
      Once the MHS L1 data are flagged correctly, this solution is subject to change.