[wpimath] Fix Rotation2d interpolation in Java (#4125)

Fixes #4112.

wpimath/src/main/java/edu/wpi/first/math/geometry/Rotation2d.java

@@ -206,6 +206,6 @@ public class Rotation2d implements Interpolatable<Rotation2d> {
   @Override
   @SuppressWarnings("ParameterName")
   public Rotation2d interpolate(Rotation2d endValue, double t) {
-    return new Rotation2d(MathUtil.interpolate(this.getRadians(), endValue.getRadians(), t));
+    return plus(endValue.minus(this).times(MathUtil.clamp(t, 0, 1)));
   }
 }