Adjusting time series range does not move the initial time step correctly

[Carlos-Alegre]

Describe the bug
When modifying the starting point of a time series, the initial time step does not change appropiately, and instead simulates from the index 0.

To Reproduce
Steps to reproduce the behavior:

1. Move the initial time step of the time series forward
2. Simulate a DCOPF with time series
3. The results will be the same but the timestep will have shifted