Remove `diffpy.utils` from `conda.txt` and `pip.txt` when support for Python 3.12 is removed

[cadenmyers13]

Problem

This was added so we could use our custom deprecator. A built-in deprecator is available for python > 3.12, so once we drop support for Python 3.12 we can remove diffpy.utils (and all its mentions).

[stevenhua0320]

@sbillinge I think now we still need diffpy.utils as diffpy.srfit requirement as we have introduced a lot of deprecators in the format of diffpy.utils.

[cadenmyers13]

@stevenhua0320 python>=3.13 has a built in deprecated decorator with the same API as we have, so we can remove it and the deprecator will still work the same. However, I think I added load_data so we might still want to include it. Need to double check this

[stevenhua0320]

@sbillinge I realized that we might need to move this to a much later release version since we should close this when we drop the support for Python 3.12, which now it is not an appropriate time to do this.

[sbillinge]

Thanks @stevenhua0320 I moved this to a later release