Fix, improve error messages in engine.constructObjectiveFromMessage()

[NiloCK]

Related to statechannels/go-nitro-testground#134 (or, at least, to the debugging of this issue)

PR:

• fixes an error message that declared a virtualfund had failed when in fact a virtualdefund had failed
• augments the error messages to include the ID of the failed objectives
• adds a small helper function to standardize these error messages

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Code quality

• I have written clear commit messages
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• This change does not have an unduly wide scope
• I have separated logic changes from refactor changes (formatting, renames, etc.)
• I have commented my code wherever necessary (can be 0)
• I have added tests that prove my fix is effective or that my feature works, if necessary
• I have added comprehensive godoc comments

Project management

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[github-actions]

🧪 Testground Run for d802855

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