dvp build does not error out if "type" field is omitted from plugin schema definitions

[ravi-cm]

** Expected Behavior**
dvp build should error out that type is a required field and missing from the schema definition.

** Actual Behavior**
dvp build allows omission of type and upload succeeds. This can cause runtime issues.

Steps To Reproduce the Problem

1. Create a plugin schema file with repository definition missing "type":"object" line.
2. Run "dvp build" - which succeeds.
3. Run dvp upload and upload the artifact to an engine which will cause an exception on the engine.