Always set the monster animation when ChangeAnimationData is called

Required updating AnimationInfo to handle being passed 0 for the total framecount, previously it would call clamp with min > max which was invalid.

Source/engine/animationinfo.cpp

@@ -166,7 +166,11 @@ void AnimationInfo::ChangeAnimationData(const CelSprite *celSprite, int numberOf
 {
 	if (numberOfFrames != NumberOfFrames || ticksPerFrame != TicksPerFrame) {
 		// Ensure that the CurrentFrame is still valid and that we disable ADL cause the calculcated values (for example TickModifier) could be wrong
-		CurrentFrame = clamp(CurrentFrame, 1, numberOfFrames);
+		if (numberOfFrames >= 1)
+			CurrentFrame = clamp(CurrentFrame, 1, numberOfFrames);
+		else
+			CurrentFrame = 0;
+
 		NumberOfFrames = numberOfFrames;
 		TicksPerFrame = ticksPerFrame;
 		TicksSinceSequenceStarted = 0;

Source/monster.h

@@ -229,12 +229,8 @@ struct Monster { // note: missing field _mAFNum
 		auto &animationData = this->MType->GetAnimData(graphic);
 		auto &celSprite = animationData.GetCelSpritesForDirection(direction);
 
-		if (celSprite) {
-			// Passing the Frames and Rate properties here is only relevant when initialising a monster, but doesn't cause any harm when switching animations.
-			this->AnimInfo.ChangeAnimationData(&*celSprite, animationData.Frames, animationData.Rate);
-		}
-		// This function is called during level load for some monsters without animations, in those cases AnimInfo is default initialised
-		// with zero/nullptr values for all the properties ChangeAnimationData would otherwise set.
+		// Passing the Frames and Rate properties here is only relevant when initialising a monster, but doesn't cause any harm when switching animations.
+		this->AnimInfo.ChangeAnimationData(celSprite ? &*celSprite : nullptr, animationData.Frames, animationData.Rate);
 	}
 
 	/**