Fix T76598: GPencil - Set a lower limit for Thickness modifier

The old value was too high. Now, the limit of pressure is 0, but anyway, the stroke will be always visible because there is a minimum thickness of 1 pixel.

source/blender/gpencil_modifiers/intern/MOD_gpencilthick.c

@@ -139,7 +139,7 @@ static void deformStroke(GpencilModifierData *md,
 
     pt->pressure = interpf(target, pt->pressure, weight);
 
-    CLAMP_MIN(pt->pressure, 0.1f);
+    CLAMP_MIN(pt->pressure, 0.0f);
   }
 }