add loading state for publishing a new sub

[plebeius-eth]

Rinse, [May 6, 2024 at 12:36:45 PM]:
a sub is created but not published when typeof sub.createdAt === "number" && !sub.updatedAt. We should have a way to show the user that the sub is created but it's getting published in the background
creating a sub is instantaneous, but publishing to the network (which will make typeof sub.updatedAt === "number") could take a while

[plebeius-eth]

1bc7102

[estebanabaroa]

we need to leave this open as this is not a great way to get the state, at some point useStateString(subplebbit) and useFeedStateString() should automatically get the state 'publishing-ipns' of a starting sub, and there will be no need for this hack. we need to wait for this to be implemented in plebbit-js plebbit/plebbit-js#41