mesh: shell: Fix health publication message size
mesh: shell: Fix health publication message size

The Health Current Fault message size was being set too small to fit
any faults. Use a macro to make sure the size gets applied in both
places where appropriate.

X-Original-Commit: 45a585586ce397337bae28f485f31f1e15b6b298

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