profiles: qutebrowser: add @sound to private-etc

[amano-kenji]

No description provided.

[kmk3]

The @sound group is automatically included when nosound is not used:

• firejail/src/firejail/fs_etc.c

  Lines 66 to 73 in e82d3a3

  	// str can be NULL
  	char *fs_etc_build(char *str) {
  	while (etc_list[etc_cnt++]);
  	etc_cnt--;
  	if (!arg_nonetwork)
  	etc_copy_group(&etc_group_network[0]);
  	if (!arg_nosound)
  	etc_copy_group(&etc_group_sound[0]);

[kmk3]

But to be fair, some profiles do have @sound, so it's unclear when it's
intended to be used.

@rusty-snake Thoughts?

[rusty-snake]

@rusty-snake Thoughts?

No.
It is document.

[kmk3]

No. It is document.

I have no idea what you mean, can you clarify?

[rusty-snake]

No thought about @sound usage.

The behavior of private-etc in the absence of nosound is documented.

[kmk3]

No thought about @sound usage.

The behavior of private-etc in the absence of nosound is documented.

Since it's already working as intended and it's documented, let's leave it as
is for now.