[Feature] Checking the sample rate of a track

## Description

Hi. If I have a track with a sample rate of 48000 and when I load it into the spleeter, the output file is saved with a sample rate of 44100 (as written in the config files). This causes the track to stretch by 10% or so. Is it possible to adjust the sampling rate, and if not, then we can simply add such a feature, for example, we can pass the frame rate to the splitter constructor or read it directly inside from the file.

I will be grateful for the reaction.

Start by tracing how the splitter constructor, input file, and config files determine the output sample rate. Reproduce the reported 48000-to-44100 behavior, then define whether the rate should be read from the input or passed to the splitter and verify that the output no longer stretches the track.

Written by the indexing model from the issue text.