reverting some changes in the UE that were introduced by...

reverting some changes in the UE that were introduced by nr_polar_encoder_optimizations to make UE work again on real-time testbench. Now at least the PDCCH can be detected and used for time tracking. However, the DCI is not yet decoded (this will be fixed on branch nr_pdcch_fixes). The reverted changes are most notably passing the correct slot number to slot_fep in phy_procedures_nrUE. This will have to be changed as well in the future when we pass to slot-based processing at the UE.