Fix: Output dipole moments in Cartesian coordinates for arbitrary lattices in RT-TDDFT

[AsTonyshment]

Fix the shared RT-TDDFT dipole output to report Cartesian x/y/z components for arbitrary lattices. Previously, projections along reciprocal lattice directions were incorrectly labeled as Cartesian components.

Writing $\rho(\boldsymbol{r})$ as the signed charge density and $\widehat{\boldsymbol{g}}_1$ as the unit vector along the first reciprocal lattice vector, the x component changes from

$$p_x^{\mathrm{old}}=\int\rho(\boldsymbol{r})(\boldsymbol{r}\cdot\widehat{\boldsymbol{g}}_1)\ \mathrm{d}^{3}r\qquad\longrightarrow\qquad p_x^{\mathrm{new}}=\int\rho(\boldsymbol{r})x\ \mathrm{d}^{3}r$$

The same correction applies to y and z.

PR #6441 fixed a similar coordinate-transformation bug in the length-gauge electric field; the corresponding issue in dipole output remained unnoticed until now.