WpState fails to store alsa streams

Alsa streams have the "[]" characters in the node name and GKeyFile doesn't accept them.

Steps to reproduce:

> gst-launch-1.0 audiotestsrc volume=0.2 ! alsasink device="pipewire:ROLE=Music"

Which creates this node:

id 52, type PipeWire:Interface:Node/3
 		factory.id = "7"
 		client.id = "51"
 		application.name = "gst-launch-1.0"
 		node.name = "PipeWire ALSA [gst-launch-1.0]"
 		media.class = "Stream/Output/Audio"
 		media.type = "Audio"
 		media.category = "Playback"
 		media.role = "Music"

And WpState asserts:

C 10:41:36.612424               GLib (null):(null):(null): g_key_file_set_value: assertion 'g_key_file_is_key_name (key)' failed