add data-block-style attr when necessary

Author: kaeizen

src/components/block-wrapper/index.js

@@ -41,8 +41,8 @@ const BlockWrapper = memo( props => {
 		// We force-removed the block alignment wrapper div (see src/blocks.js),
 		// so we need to add our own data-align attribute.
 		'data-align': align,
-		// Add data-block-style attribute to replace data-block selectors.
-		'data-block-style': blockStyle,
+		// Add data-block-style attribute to replace data-block selectors
+		...( blockStyle ? { 'data-block-style': blockStyle } : {} ),
 	} )
 
 	// Remove the custom CSS names here because we will be adding it in the BlockDiv component, we need to do this for our current styles to work.