* mobile: don't retain transient []byte in CallMsg.SetData

Go mobile doesn't copy []byte parameters, for performance and to allow
writes to the byte array be reflected in the native byte array.
Unfortunately, that means []byte arguments are only valid during the
call it is being passed into.

CallMsg.SetData retains such a byte array. Copy it instead

Fixes #14675

* mobile: copy all []byte arguments from gomobile

To avoid subtle errors when accidentially retaining an otherwise
transient byte slice coming from gomobile, copy all byte slices before
use.

* mobile: replace copySlice with common.CopyBytes