Update spacer in Lettre post template (#7098)

lettre/parts/header-archive.html

@@ -6,8 +6,8 @@
 <!-- wp:navigation {"overlayMenu":"always","overlayBackgroundColor":"background","overlayTextColor":"foreground","layout":{"type":"flex","setCascadingProperties":true,"justifyContent":"right"},"style":{"typography":{"fontStyle":"normal"}},"fontSize":"x-large"} /--></div>
 <!-- /wp:group -->
 
-<!-- wp:spacer {"height":"200px"} -->
-<div style="height:200px" aria-hidden="true" class="wp-block-spacer"></div>
+<!-- wp:spacer {"height":"100px"} -->
+<div style="height:100px" aria-hidden="true" class="wp-block-spacer"></div>
 <!-- /wp:spacer -->
 </div>
 <!-- /wp:group -->