[BUG] Unable to populate HandoverRequired with HO Type = 5GS to 4G

**Describe the bug**
Adding support for setting the target eNodeB ID, similar to the SetTargetGnodeB function, in the handover-required.go file for testing 5g to 4g handover.

**To Reproduce**
Execute the following command:
```
./packetrusher multi-ue --tr 2000 --ngh 7000 -n 1
```

**Expected behavior**
The function should support assigning the TargeteNB-ID structure as specified below:
```
TargeteNB-ID ::= SEQUENCE {
globalENB-ID GlobalNgENB-ID,
selected-EPS-TAI EPS-TAI,
iE-Extensions ProtocolExtensionContainer {{TargeteNB-ID-ExtIEs}} OPTIONAL
}
```
However, implementation attempts have been unsuccessful. The goal is to test 5G to 4G handover functionality.

**Screenshots**
Currently, the function supports the following structure:


Expected structure:


**Request for Assistance**
Could someone help test this functionality or provide guidance on implementing the desired changes? Any suggestions for achieving the required behavior would be greatly appreciated.

Start in handover-required.go and compare the requested TargeteNB-ID handling with the existing SetTargetGnodeB function. Reproduce the issue with ./packetrusher multi-ue --tr 2000 --ngh 7000 -n 1, then verify that HO Type = 5GS to 4G can populate the TargeteNB-ID structure shown in the issue.

Written by the indexing model from the issue text.