Update index.yml

Removing Preferred migration accelerator: Next pathway.     We should only have our own / partners should be on the partners page.
-------
cc: @WilliamDAssafMSFT

Author: MarkPryceMaherMSFT

articles/synapse-analytics/migration-guides/index.yml

@@ -53,10 +53,6 @@ landingContent:
             url: https://customers.microsoft.com/en-GB/story/816187-neogrid-professional-services-azure-synapse-analytics
           - text: "Customer story: Walgreens"
             url: https://customers.microsoft.com/en-us/story/778746-walgreens-retailers-azure-analytics
-      - linkListType: deploy
-        links:
-          - text: "Preferred migration accelerator: Next Pathway"
-            url: https://www.nextpathway.com/
   - title: From IBM Netezza
     linkLists: 
       - linkListType: overview