Add note suggesting that it might take some time before the agent is visible

[devjsc]

In Register a local Agent Function on the Agentverse and Make your agents AI Engine compatible (as mentioned in point 1, there is some repetition) it says to paste your local's agent address in the Agentverse page.

However, I found that it takes at least 5 minutes after the launch of the local agent before the address is recognised, and until then, it gives an error like in the following screenshot: see (https://github.com/fetchai/docs-v2/issues/598)

Elsewhere in the guides, there is a brief mention of a 5 minutes wait (in Agent Handlers). However I feel like it might be useful to the users to add another mention in the sections mentioned above, as it wasn't obvious to me that I had to wait before the agent would be recognised.

[devjsc]

cc @ManueleSigona

[devjsc]

This is fixed 👍