Remove sarepy from dependancies

[samtygier-stfc]

Issue

We migrated from sarepy to algotom in #1023, but had to keep the dependency to enable building old documentation.

This was resolved in #1150, so now its possible to remove the package

Description

Remove sarepy from dependancies and remove dtasev channel

Acceptance Criteria

Automated testing should all pass

Documentation

Not needed

[coveralls]

coverage: 73.019%. remained the same
when pulling a884c8f on 1150-remove-sarepy
into b866326 on main.

[JackEAllen]

Looks good! I did notice that we need to update some a Docstring and tooltip that still reference Sarepy that we should swap to say using Algotom which make sense to do as part of this PR.

mantidimaging/core/operations/remove_stripe_filtering/remove_stripe_filtering.filter_func Line 49:

:param filtering_dim: Whether to use a 1D or 2D low-pass filter. This
   uses different Sarepy methods.

and:
mantidimaging/core/operations/remove_stripe_filtering/remove_stripe_filtering.register_gui Line 121:

tooltip="Whether to use a 1D or 2D low-pass filter. "
    "This uses different Sarepy methods")

[coveralls]

coverage: 72.992% (-0.03%) from 73.019%
when pulling b141b19 on 1150-remove-sarepy
into b866326 on main.

[JackEAllen]

Thanks for swapping the last few references from sarepy to algotom. Looks good!