NTN: Fixing variable ULDLduplex issue for NTN bands

- Duplex is assumed to be static but for NTN bands (and also for some non NTN
  bands), it is not static.
- Tx-RX Duplex is defined in section 5.4.4 of 38.101-5 (for NTN) specs v1809
- For example: In NTN-OTA testing, the GEO satellite operator configured in
  band 256 the DL, UL frequencies with duplex of 185Mhz.