Update Icepack to #daa41638c6cef, enforce minimum snow grain radius (#1089)

Update Icepack to #daa41638c6cef to include

Enforce minimum snow grain radius (#552)

If the snow grain radius is set to zero, possibly because of zapping small ice or if ice disappears mid-timestep, then updates of snow grain radius will produce NaNs. Snow grain radius is usually bounded between a min and max so this generally doesn't happen, but a recent coupled E3SM bgc run crashed with this error. While the error seems to be relatively rare, this bug fix changes answers when the snow grain radius is nonzero but still less than the minimum.

Author: apcraig