Configurable mob blindness

Ported from https://github.com/raltsmc/mobblindness

purpur-server/minecraft-patches/sources/net/minecraft/world/entity/LivingEntity.java.patch

@@ -31,6 +31,24 @@
                      }
                  } else if (this.getAirSupply() < this.getMaxAirSupply()) {
                      this.setAirSupply(this.increaseAirSupply(this.getAirSupply()));
+@@ -1018,6 +_,17 @@
+             }
+         }
+ 
++        // Purpur start - Configurable mob blindness
++        if (lookingEntity instanceof LivingEntity entityliving) {
++            if (entityliving.hasEffect(MobEffects.BLINDNESS)) {
++                int amplifier = entityliving.getEffect(MobEffects.BLINDNESS).getAmplifier();
++                for (int i = 0; i < amplifier; i++) {
++                    d *= this.level().purpurConfig.mobsBlindnessMultiplier;
++                }
++            }
++        }
++        // Purpur end - Configurable mob blindness
++
+         return d;
+     }
+ 
 @@ -1372,6 +_,24 @@
                  this.stopSleeping();
              }