Enhance exception handling when testing an exploit code

[claudioantonio]

Context

Due to #119 it would be important to handle the exception when there is an error on the inspect call associated to the test exploit code feature. The expected result is to receive an Json, but when there is an error we receive a string then the app show the truncated message. Unexpected token 'F', "Failed to "... is not valid JSON

Expected behavior

Check the result and present the full message, which in the case of #119 the message was: Failed to inspect state: session is tainted

[guidanoli]

I think the inspect call indeed returned a JSON as expected, and that this message was, as expected, encoded through reports. You can see on the front-end code that it only writes to the shell component (through setExploitOutput) after processing the response body as a JSON.

https://github.com/crypto-bug-hunters/bug-buster/blob/89ab74c05d5da0b5c78c85d5e8a0ffc51c836deb/frontend/src/app/bounty/%5BbountyId%5D/exploit/page.tsx#L101-L109