fix: Convert Item links to Website Item links in Item Card Group template data

[marination]

Issue:

• Item Cards did not redirect anywhere, this is because Item master does not have the route field anymore
• This template was still fetching Item master data

Fix:

• Changed link option to Website Item in Item card group template
• patch to convert pre-existing data
• 

To test:

• Make a web page and use Item card Group page block, add items to the block.
• check if the cards are responsive on the web page

[marination]

server test failure is unrelated, have notified HR maintainer to fix it (test_against_leave_application_validation_after_submit)