SYCL: Simplify RB dihedral force calculation
We are avoiding computing sin/cos of the atan2, instead using the operands directly.
Avoids regression test failure on Intel Gen8/Gen9 iGPUs. Tested on Intel Max 1100 and AMD MI250X to not introduce any regressions.
Closes #4686 (closed)
Edited by Andrey Alekseenko