Fixing the tests for Mk-MMD loss such that they still pass properly on a GPU and CPU

[emersodb]

PR Type

Fix

Short Description

Clickup Ticket(s): Link

The Tests for Mk-MMD loss were not properly handling device allocation if run on a GPU. This PR fixes that issue along with a small device bug in the loss function when a tensor of gammas were manually provided rather than created by default.

Tests Added

N/A