Rename the Yang file to reflect changes made in the Rel 18
Desc
Exec ./build-adapter.sh --adapter is failed due to error on
3.750 cp: cannot stat '/adapter/scripts/available-yangs/_3gpp-5gc-ecmconnectioninfo.yang': No such file or directory
Reason https://forge.3gpp.org/rep/sa5/MnS/-/commit/819f05af6ae5c8fe4ab13026da78d29e5630bf78
Fixes rename related file accordingly