Confirms that the key pair have rights to query a property
OAuth2 keypairs are associated with CMS users. Whilst keypairs can belong to any registered user any API feature that directly changes or exposes a property should call this class to confirm that the key pair user has rights to perform the action on the specific property. Keypairs need both therefore to have been given access to the Scope in question and additionally it needs to pass this test.
Tests keypair to confirm that they have rights to access the property. If the user is a super property manager or the system keypair then the answer is yes. If not, then the managers_propertys_xref table is queried to check that the property is one of the manager's properties