Checks and fixes for pasting copied reference fields

[Logyrac]

Description

When copying and pasting values from a property's context menu, there were currently no checks in place to avoid certain issues:

• Attempting to paste to a property who's current value is null causes an error due to JsonUtility.FromJsonOverwrite
• Pasting a value from one type into a field of a different type, which may or may not have the appropriate fields

Added logic to check for potential conflicts and handle them.

Changes made

• Store the copied field type in SessionState for use in type safety comparisons
• Test for potential conflicts and return result as enum for handling
• Implement menu items for different results:
  • When no issues are detected or copied value is empty continue as before, with no change
  • When copied value is different type than current value, but still valid for the property, then pasting will create a new instance via Activator and then merge the JSON in. The Paste menu item shows a warning that the type will be overwritten.
  • When current value is null, create a new instance using Activator before using JSON overwrite to avoid error.
  • When copied value type is not valid for the field (uses TypeCandiateService [which is mis-spelled as a note, should be Candidate]) then disable the menu item with message explaining incompatible type.
  • When copied value refers to an invalid of non-existent type (type may be deleted between copy and paste) add disabled item with text stating invalid type
• Exposed function for evaluating qualification from TypeCandiateService, which evaluates the intrinsicTypePolicy and typeCompatibilityPolicy, for use in testing field combability in pasting, so that the TypeCandiateService is a single point of truth on this test.