Fix C++ compilers warnings

[traversaro]

• Fix YARP 3.7 compatibility fixes https://github.com/robotology/human-dynamics-estimation/issues/296
• Fix control reaches end of non-void function warning removes the only remaining warning in the CI

[traversaro]

Please ignore the macOS failure, it is a network flake that happens only from time to time and will be fixed by https://github.com/robotology/human-dynamics-estimation/pull/302 .

[traversaro]

Thanks, we can wait the checks and merge

FYI @lrapetti CI successful.

[lrapetti]

Thanks @traversaro