Wireshark: Print vbucket as decimal instead of hex

When using the Couchbase dissector in Wireshark (v3.6.1) vBuckets are printed in hex:

17471	2022-02-09 13:43:34.497090	192.168.178.80	11999	192.168.178.80	53025	DCP Snapshot Marker Request, Opcode: 0x56, VBucket: 0x3e5		

Compare this to when we print vbuckets in kv_engine logs etc where they are always printed as decimal - typically in the format vb:997.

We should modify Wireshark's dissector to match the normal format.