Local NTP: use 29px of spacing below logo

Brings the Local NTP back in line with the spacing required for certain
overly-tall Doodles.

Bug: 761994
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I7bf8e6aa9e5a3a7035c14b0e1a4c2c2679decc07
Reviewed-on: https://chromium-review.googlesource.com/824239Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Chris Pickel <sfiera@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524032}

chrome/browser/resources/local_ntp/local_ntp.css

@@ -14,7 +14,7 @@ html {
 
   --logo-height: 200px; /* Normal height of a doodle. */
   --logo-margin-top: 56px; /* Expected OGB height, so logo doesn't overlap. */
-  --logo-margin-bottom: 24px; /* Between logo and fakebox. */
+  --logo-margin-bottom: 29px; /* Between logo and fakebox. */
 
   --tile-height: 128px;
   --tile-margin: 16px;