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

wpimath/src/main/native/include/frc/geometry/Translation3d.h

@@ -66,6 +66,16 @@ class WPILIB_DLLEXPORT Translation3d {
         m_y{units::meter_t{vector.y()}},
         m_z{units::meter_t{vector.z()}} {}
 
+  /**
+   * Constructs a 3D translation from a 2D translation in the X-Y plane.
+   *
+   * @param translation The 2D translation.
+   * @see Pose3d(Pose2d)
+   * @see Transform3d(Transform2d)
+   */
+  constexpr explicit Translation3d(const Translation2d& translation)
+      : Translation3d{translation.X(), translation.Y(), 0_m} {}
+
   /**
    * Calculates the distance between two translations in 3D space.
    *