fix(virtual-background) Style fix (#13016)

react/features/virtual-background/components/VirtualBackgrounds.tsx

             display: 'flex',
             alignItems: 'center',
             justifyContent: 'center',
+            textAlign: 'center',
             ...withPixelLineHeight(theme.typography.labelBold),
             color: theme.palette.text01,
             objectFit: 'cover',