Extensions: fix navigation long text layout

Bug: 817713
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I8c2723eb80a9301e74048df4e2b1e65a03b8ea61
Reviewed-on: https://chromium-review.googlesource.com/943523Reviewed-by: Hector Carmona <hcarmona@chromium.org>
Commit-Queue: Scott Chen <scottchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541191}

chrome/browser/resources/md_extensions/sidebar.html

@@ -34,10 +34,11 @@
         /* Ensure the focus outline appears correctly (crbug.com/655503). */
         -webkit-margin-end: 4px;
         -webkit-padding-start: 24px;
+        align-items: center;
         color: inherit;
-        display: block;
+        display: flex;
         font-weight: 500;
-        line-height: 40px;
+        min-height: 40px;
         position: relative;
         text-decoration: none;
       }