This commit properly is filing the dci_format but the
rx_ind and dl_ind has not been updated in the NR UE
prior to sending to gNB. The chnages in this commit
to properly fill the dci_format include:
- filling the dci canidates every slot indiction
- checking for a dl_tti/ul_tti containing a dci
- when dci payload is received we use the filled
  dci canidates to update the dci_format

Also, a bug in LTE UE is found where we are indexing
passed the end of ue_sdu array. We added a check for this.
Furthermore, in the nr_ue_scheduler we were utilizing
tx_req but the memory wasnt properly initialized.