Log actual exception in E2E job failure report log

in the final 'a test has failed' message for e2e tests, it only reports the SSM top-level error rather than the actual cause of the integration test failure exception.

Such as:

```
V-2 An e2e instance run has failed
{
"jobId": "aws-eks-anywhere-test:xxxxxxxxxxx",
"instanceId": "i-xxxxxxxxxxx",
"tests": "TestVSphereKubernetes121UbuntuRegistryMirrorAndCert",
"status": "fail",
"error": "error running e2e tests on instance i-xxxxxxxx: failed to execute ssm command"
}
```

Instead of "failed to execute ssm command", the response should contain the exception that caused the SSM command to fail (i.e. the error encountered during the execution of the e2e binary)

Locate the final “a test has failed” E2E report and the SSM command execution path, then reproduce the failure described for TestVSphereKubernetes121UbuntuRegistryMirrorAndCert. The error field should report the exception from the E2E binary rather than only “failed to execute ssm command”.

Written by the indexing model from the issue text.