If I inject a non-existant oav device I get an error like the following:

org.python.core.PyException: java.util.concurrent.ExecutionException: java.util.concurrent.ExecutionException: uk.ac.diamond.daq.bluesky.client.error.HttpValidationError: ValidationError[locations=[body, params, oav], message=Value error, Device oav is not of type dodal.devices.oav.oav_detector.OAV, type=value_error, input=oav]

This message implies that there is an oav device but it is just the wrong type it would be better to provide a specific message that says the device cannot be found and list the available devices so that we can be helpful.

Acceptance Criteria

• When I inject a non-existant device the error message is more helpful