Use an api call from the whitelist to check if the http api is available

[olizilla]

We're using a call to.id() to verify that the ipfs instance is working. That triggers an confirmation modal when using window.ipfs. We don't want to trigger that if the app doesn't need the id of the current node. This should be swapped to a call that is on the whitelist: https://github.com/ipfs-shipyard/ipfs-companion/blob/master/add-on/src/lib/ipfs-proxy/acl-whitelist.json

[olizilla]

This should also be something from the read-only / gateway api as per https://github.com/ipfs/go-ipfs/blob/727bf49eff7ff61936aee6d4674ae3e7ad0aaddb/core/commands/root.go#L155-L187

[olizilla]

Fixed in #15