composer: register only vsync_2_4 callback

Composer 2.4 extends vsync callback by exposing a new vsync_2_4
callback. Both should not be registered at the same time.

Test: rev up composer to 2.4 and test refresh rate switching
Bug: 141329414
Change-Id: If41f45cab21ed16a7b2f36b3b95fb3591b04c900