fix: removing enterprise specific code from platform

[kiram15]

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[pwnage101]

Wouldn't hurt to add this unit test (from the claude PR) to make sure the signal gets called, and maybe add in the docstring that external plugins may depend on it. This is a bit of an insurance policy against regressions.

https://github.com/openedx/openedx-platform/pull/38100/changes#diff-6daca8ceb97506291e5ae48e67b83b1406fdf689e8f73c83542d2a3eaa93fe4eR1521-R1534

[pwnage101]

DO NOT MERGE before updating this PR to bump edx-enterprise to include changes from openedx/edx-enterprise#2559