Guard Against crashes in HTTP when making addition nodeos calls

[ericpassmore]

Don't crash when making calls to nodeos in service on an HTTP request. Interactions should be treated as suspect, and a failure should be returned to the client.

We talked with Guillaume. Turn out he was using a build from a fork which had pulled a version post 4.0.3 by mistake:

Checked client repo and indeed they had a change not in our release/4.0 branch, which causes the issue.

They will rebase their repo on the right tag (4.0.3) which will solve the issue for them.

The change causing the leap crash has not been released (it is in our main branch), and I have a fix for it. So in a sense the mistake they made was lucky for us, as it allowed us to catch the leap issue before the code was officially released.

To be 100% clear, no 4.0.x leap release is subject to the crash in http_plugin.