[202012][sonic-platform-daemons] submodule update

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

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