REF: msct_pca: changed the figure title in plot_omega
REF: msct_pca: changed the figure title in plot_omega

Former-commit-id: 8ac25376ce9d403a6a342601ad193b7979603505
Former-commit-id: 146e01be02d715b26bfebb48f456831fd261f694
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox