Overlapping condition changed (TheAlgorithms#7314)

Overlapping happens not when centers of circular bodies are in the same point, but when the distance between them is smaller than the sum of their radii.

Author: kvadrik

src/main/java/com/thealgorithms/physics/ElasticCollision2D.java

@@ -41,7 +41,7 @@ public static void resolveCollision(Body a, Body b) {
         double dy = b.y - a.y;
         double dist = Math.hypot(dx, dy);
 
-        if (dist == 0) {
+        if (dist < a.radius + b.radius) {
             return; // overlapping
         }