mgr/dashboard: Fix the table mouseenter event handling test

mgr/dashboard: Fix the table mouseenter event handling test

This test only failed if all suites were run, for some reason the window
object got replaced with a mock window. The workaround is not to use
the window object, but mock the called function in order to call the
values as expected by window.

Fixes: https://tracker.ceph.com/issues/40580
Signed-off-by: Stephan Müller <smueller@suse.com>
(cherry picked from commit efc79990b25cd6fe4be1ab640305aaa6c829740d)

Conflicts (trivial + linting issue):
	src/pybind/mgr/dashboard/frontend/src/app/shared/datatable/table/table.component.spec.ts