Add fallbacks for Kashmiri (ks)

[srish]

This PR is about adding ur and hi as fallbacks for Kashmiri language.

Related patches open in Gerrit:

• https://gerrit.wikimedia.org/r/c/mediawiki/core/+/948987
• https://gerrit.wikimedia.org/r/c/translatewiki/+/948712

Bug:

• https://phabricator.wikimedia.org/T314476

[srish]

This is probably no longer needed based on recent comments in the Phab task.