[MD settings] adjust control spacing

chrome/browser/resources/settings/controls/controlled_button.html

 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_pref_behavior.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_pref_indicator.html">
 <link rel="import" href="pref_control_behavior.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="../settings_shared_css.html">
 
 <dom-module id="controlled-button">
   <template>
     <style include="settings-shared">
       :host {
+        --justify-margin: 8px;
         align-items: center;
         display: flex;
-        --justify-margin: 18px;
       }
 
       :host([enforced_]) {
         /* Disable pointer events for this whole element, as outer on-tap gets
          * triggered when clicking/tapping anywhere in :host. */
         pointer-events: none;
       }
 
       cr-policy-pref-indicator {
         /* Enable pointer events for the indicator so :hover works. Disable
@@ skipping 19 matching lines @@
 
     <template is="dom-if" if="[[hasPrefPolicyIndicator(pref.*)]]" restamp>
       <cr-policy-pref-indicator pref="[[pref]]" on-tap="onIndicatorTap_"
           icon-aria-label="[[label]]">
       </cr-policy-pref-indicator>
     </template>
 
   </template>
   <script src="controlled_button.js"></script>
 </dom-module>