[NPCs] npc_sniper fails to acquire player if they respawn after dying to them

[arbabf]

Describe the bug

If the player respawns using the hl2_gamerules entity, and they died to an npc_sniper, that npc_sniper fails to acquire them when they get into their line of sight.

Steps to reproduce

Steps to reproduce the behavior:

1. Place an npc_sniper down.
2. Die to the npc_sniper.
3. Walk into its line of sight.
4. You do not get acquired as a target.

Expected behavior

Sniper reacquires player as a target like other NPCs do.

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Additional context

Respawning the same npc_sniper (e.g. through an npc_template_maker) fixes the issue, so I guess this issue can be solved with map logic as well.