Figcaption doesn't become translation ready

[iamtakashi]

Sample markup

<!-- wp:video {"id":158} -->
<figure class="wp-block-video"><video controls src="<?php echo esc_url( get_stylesheet_directory_uri() ); ?>/assets/videos/tennis_video.mp4"></video><figcaption class="wp-element-caption">Rewatch one of the biggest matches in history.</figcaption></figure>
<!-- /wp:video -->

The string Rewatch one of the biggest matches in history. stays as is after saving the theme.

[matiasbenedetto]

A potential fix for this:
#745