detect: skip pseudo packets if sig needs real pkt

detect: skip pseudo packets if sig needs real pkt

If a signature uses a condition that requires a real packet, filter
out pseudo packets as early as possible. To do this, the SignatureMask
logic is used.

This allows for the removal of checks for pseudo packets in individual
keywords `Match` functions, which will be done in a follow up commit.

Update analyzer to output the new flag.

Ticket: #7002.