Export isBooted in IntercomContextValues

[ryan-tote]

Is your feature request related to a problem? Please describe.
Currently unable to tell if the intercom client is in a booted state which means you cannot write code similar to

if (isBooted) {
   update(...)
} else {
   boot(...)
}

Describe the solution you'd like
Export the isBooted ref from provider.tsx

Describe alternatives you've considered
Could do an in house tracking of whether the intercom client is booted or not by wrapping all of the hooks that are exported from this package but this seems like overkill