[wpimath] Add 2D to 3D geometry constructors (#7380)

wpimath/src/main/native/include/frc/geometry/Rotation3d.h

@@ -229,6 +229,16 @@ class WPILIB_DLLEXPORT Rotation3d {
     }
   }
 
+  /**
+   * Constructs a 3D rotation from a 2D rotation in the X-Y plane.
+   *
+   * @param rotation The 2D rotation.
+   * @see Pose3d(Pose2d)
+   * @see Transform3d(Transform2d)
+   */
+  constexpr explicit Rotation3d(const Rotation2d& rotation)
+      : Rotation3d{0_rad, 0_rad, rotation.Radians()} {}
+
   /**
    * Adds two rotations together.
    *