Deprecates the $course parameter in the constructor of the
core_course\output\actionbar\group_selector class. This parameter is no
longer used, as the $course object can now be obtained through the
$context class property. Additionaly, the $course class property has
been removed in accordance with this change.
This change ensures that the group selector correctly appears on the
submission page, adhering to the assignment's group mode settings or
the enforced group mode set by the course.
The group selector component should be sensitive to the current context
to ensure accurate validation and retrieval of group settings
(e.g. group mode).
