[5.0] compute_transaction should return failure trace

[heifner]

/v1/chain/compute_transaction API endpoint should return a failure trace.
This was accidently changed to false when refactoring send_transaction in 5.0.

See 4.0 impl:

leap/plugins/chain_plugin/chain_plugin.cpp

Line 2562 in 01dab51

app().get_method<incoming::methods::transaction_async>()(pretty_input, true /* api_trx */, trx_type, true /* return_failure_trace */,

Resolves #2281

[ericpassmore]

Note:start
category: Other
component: Chain-Plugin
summary: Restore failure trace to compute_transaction.
Note:end