[l4d2_smoker_drag_damage_interval] Update

[A1mDev]

Changes:
1. Removed duplicate plugins:

• l4d2_smoker_drag_damage_interval_zone
• l4d2_smoker_drag_damage_interval.

2. Removed untrusted timer-based code:

• Replaced with safer, hook-based implementation using OnTakeDamage.
• Ensures more stable and reliable drag damage behavior without unnecessary timers.