Clean yaml validator false positive output

[abaskk-msft]

Problem

• In the current validation output there is an edge case with returning output on an Invalid Schema.
• The schema structure requires that at the root of the yaml we either have a single control or an array of controls (using a OneOf json-schema statement)
  
• In a valid schema, a single evaluation path being true (object or array of objects) will make the entire schema true
• In an invalid schema, both evaluation paths will be false. Suppose we wanted to trace an error; we would have to go down both evaluation paths in the evaluation tree (one of which would always evaluate to false even if the schema was valid).
• This additional useless information is output on the console to the user and is confusing/uninformative. This pr removes the evaluation path which contains useless information.

Solution

• Among the schema evaluation path which require we have a single control object or array of control object; we find which evaluation path has the longest suffix and filter out the rest of the evaluation paths with a smaller length suffix.

Validation

• Only local test with examples I made. Perhaps we can add unit tests on the actual errors of the schema, as opposed to simply checking if the entire schema evaluated true or false