remove unneeded styles for post template (#4809)

blockbase/assets/ponyfill.css

@@ -667,8 +667,9 @@ p.has-drop-cap:not(:focus):first-letter {
 	display: none;
 }
 
-.wp-block-post-template .wp-block-post-featured-image {
-	line-height: 0;
+.wp-block-post-template {
+	margin-top: 0;
+	margin-bottom: 0;
 }
 
 .wp-block-pullquote.is-style-solid-color,

blockbase/sass/blocks/_post-template.scss

@@ -1,6 +1,4 @@
 .wp-block-post-template {
-	// Needed until https://github.com/WordPress/gutenberg/pull/35273 is merged.
-	.wp-block-post-featured-image {
-		line-height: 0;
-	}
+	margin-top: 0;
+	margin-bottom: 0;
 }