Stop passing empty $context array to hook_entity_view_mode_alter()

Problem/Motivation

#3193131: $context in hook_entity_view_mode_alter is always empty removed some stale documentation for the $context parameter to hook_entity_view_mode_alter(), which is always empty.

However, to avoid errors on modules implementing the hook, we still pass the empty parameter. We can stop passing this in Drupal 10, since modules can remove the parameter from their hook signature at any time.

Proposed resolution

Stop passing empty $context array.

Remaining tasks

Review / commit.