Fix padding and color for WebUI Settings "Advanced" toggle container

One of my recent CLs added an include of the "settings-shared" CSS
styles to basic_page.html:
https://chromium-review.googlesource.com/c/chromium/src/+/1783060

This added CSS rules for <h2> that matched the "Advanced" toggle button
container and added unwanted padding and text color.

Fix by explicitly setting the padding and color to the correct values.

See bug for screenshots pre-regression, post-regression, and with
this fix.

Bug: 1002422
Change-Id: Ia25ef9b5f4183633f1a1cdd1a15e8a741e7a7513
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1795498Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695368}

chrome/browser/resources/settings/basic_page/basic_page.html

@@ -87,11 +87,14 @@
 
       #toggleContainer {
         align-items: center;
+        color: var(--cr-primary-text-color);
         display: flex;
         font: inherit;
         justify-content: center;
         margin-bottom: 0;
         margin-top: 0;
+        padding-bottom: 0;
+        padding-top: 0;
       }
 
       #toggleSpacer {