Resolve "Specific paths cant be requested, because the underlying device goStruct can't be filled."

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

Closes #148 (closed)

interfaces/southbound/sbi.go

@@ -23,5 +23,5 @@ type SouthboundInterface interface { // nolint
 	Schema() *ytypes.Schema
 	ID() uuid.UUID
 	Type() spb.Type
-	Unmarshal([]byte, []string, ygot.ValidatedGoStruct, ...ytypes.UnmarshalOpt) error
+	Unmarshal([]byte, *gpb.Path, ygot.ValidatedGoStruct, ...ytypes.UnmarshalOpt) error
 }