Revert "audiobasesink: Don't wait on gap events" in 1.24

This reverts commit 8e923a8e.

This caused regressions, see #3303 (closed).

Without this commit, osxaudiosrc ! osxaudiosink won't work right, but since that hasn't really been a huge problem for years it's probably best to revert this until a proper solution can be figured out.

cc @thaytan