Weakness effect makes instant damage splash potions weaker

[JavierLeon9966]

Issue description

• Expected result: Instant damage splash potions dealing the same damage.
• Actual result: Instant damage splash potions damage weakened.

Steps to reproduce the issue

1. Give yourself weakness. The bigger, the more noticeable.
2. Get yourself an instant damage splash potion.
3. Change your game mode to survival and splash yourself with the potion.

OS and versions

• PocketMine-MP: 5.12.0 (git hash: a35c340)
• PHP: 8.3.0
• Using JIT: no
• Server OS: win
• Game version: Android

Crashdump, backtrace or other files

Screen_Recording_20230921_212936_Minecraft.mp4