Subtract padding on full width

* The padding is there if the whole Query Loop block isn't set as full
width. If it is set as full width, the image size calculation is very
different.

planet4-gutenberg-blocks.php

@@ -464,7 +464,7 @@ function ( $breakpoint ) use ( $column_count ) {
 				$breakpoints
 			);
 
-			$sizes_attr = 'sizes="' . implode( ', ', $sizes ) . ', 100vw"';
+			$sizes_attr = 'sizes="' . implode( ', ', $sizes ) . ', 100vw - 24px"';
 
 			// Assume all images are full width in a container.
 			$block_content = preg_replace( '/sizes=".*"/', $sizes_attr, $block_content );