NsdService: minor cleanups

Minor cleanups in switches of processMessage and handleNativeEvent.

Test: no functional changes
Bug: 33074219

(cherry picked from commit 23dba85fff01a9f51beea8ce811fc98b582f8e71)

Merged-In: I9ad4ce812c0d2c02a671a7a871ad427e4ce29b4a
Change-Id: Ic029cc9fa007d8c485f64f4afcbd4dc10da1ae29
1 file changed