[202012][sonic-platform-daemons] submodule update (#10121)

4dc2d0a (HEAD -> 202012, origin/202012) Clear all data from DB table when the daemon stops (#228)
1df28d7 [ycabled] increase UT coverage of ycabled daemon (#238)

Signed-off-by: vaibhav-dahiya <vdahiya@microsoft.com>