ipc: make bar <bar_id> mode|hidden_state behave as documented

[alebastr]

sway-bar(5) says:

For compatibility with i3, bar mode <mode> [<bar-id>] syntax is supported along with the sway only bar <bar-id> mode <mode> syntax.

while the actual behavior is that bar_cmd_mode ignores already selected config->current_bar and applies the change to all the configured bars.

Before:

00:00:15.799 [INFO] [sway/commands.c:257] Handling command 'bar bar-0 mode dock'
00:00:15.799 [DEBUG] [sway/commands/bar.c:66] Selecting bar: bar-0
00:00:15.799 [DEBUG] [sway/commands.c:428] Subcommand: mode dock
00:00:15.799 [DEBUG] [sway/commands/bar/mode.c:33] Setting mode: 'dock' for bar: bar-0
00:00:15.799 [DEBUG] [sway/commands/bar/mode.c:33] Setting mode: 'dock' for bar: bar-1
00:00:15.799 [DEBUG] [sway/ipc-server.c:347] Sending barconfig_update event

Note that the barconfig_update event is only sent to the config->current_bar (bar-0), even if we just updated mode for all the bars.

After:

00:00:22.724 [INFO] [sway/commands.c:257] Handling command 'bar bar-0 mode dock'
00:00:22.724 [DEBUG] [sway/commands/bar.c:66] Selecting bar: bar-0
00:00:22.724 [DEBUG] [sway/commands.c:428] Subcommand: mode dock
00:00:22.724 [DEBUG] [sway/commands/bar/mode.c:33] Setting mode: 'dock' for bar: bar-0
00:00:22.724 [DEBUG] [sway/ipc-server.c:347] Sending barconfig_update event

[emersion]

Thanks!