[L1TopoEvent] Make slicing and narrowing casts explicit
Turn implicit slicing and narrowing into explicit. Multiple cases of each of the following clang-tidy warnings are fixed:
- narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [bugprone-narrowing-conversions]
- slicing object from type ... to 'BaseTOB' discards ... bytes of state [cppcoreguidelines-slicing]
- slicing object from type ... to 'BaseTOB' discards override 'print' [cppcoreguidelines-slicing]
- slicing object from type ... to 'BaseTOB' discards override 'tobType' [cppcoreguidelines-slicing]