audio-bridge: remove --print-pid from dbus session (broken in containers)

dbus-daemon --print-pid=N opens fd N for writing; under tini this fails
with 'Writing to pipe: Invalid argument'. Just use --fork for daemonization.

infra/audio-bridge/entrypoint.sh

@@ -18,7 +18,7 @@ sleep 0.5
 # Session DBus (needed by PipeWire for portal/jackdbus-detect modules).
 # Use XDG_RUNTIME_DIR=/run/user/0 so dbus-launch puts socket there.
 export XDG_RUNTIME_DIR=/run/user/0
-dbus-daemon --session --address=unix:path=/run/user/0/bus --fork --print-pid 3
+dbus-daemon --session --address=unix:path=/run/user/0/bus --fork
 sleep 0.3
 
 # BlueZ (Bluetooth stack). --compat = legacy mode for older audio devices.