mesh: Group resends in proxy nodes
mesh: Group resends in proxy nodes

Resend transport segments for groups on the advertiser interface, even
if a connected proxy node holds the group.

this is port of 9d272db9e11c149aced0d01087f2e92810e4dae9

apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble,apache/mynewt-nimble