Looks like the Azure B2C v2 does not support the Keep Me Signed In feature as of today. You can refer this document on the same.
Also, as per another document, the DataUri value is to be urn:com:microsoft:aad:b2c:elements:unifiedssp:1.1.0
and that should not be changed.
Hope this helps. Let us know if we can assist you further.
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