If you opened element and entered a jitsi conference straight away
in the room you landed in, your jitsi display name would be your
matrix username rather than your display name. This was because
OwnProfileStore was still busy fetching your profile from the server
while the room, and therefore jitsi widget, was rendered.
Blocking these widgets loading on this profile fetch completing isn't
really an option, so store the profile data in localstorage and seed
OwnProfileStore with the values from there.
Bonus: the name in the top left will now be your display name as
soon as the app is loaded, rather than being your username for the
first several seconds after you load the app.
Fixes https://github.com/vector-im/element-web/issues/16577
