Remove wrapper around manage spaces button in menu (#24506) (#24525)

Fixes #23544

x-pack/plugins/spaces/public/components/__snapshots__/manage_spaces_button.test.tsx.snap

@@ -4,7 +4,6 @@ exports[`ManageSpacesButton doesn't render if user profile forbids managing spac
 
 exports[`ManageSpacesButton renders as expected 1`] = `
 <EuiButton
-  className="manage-spaces-button"
   color="primary"
   fill={false}
   iconSide="left"

x-pack/plugins/spaces/public/components/manage_spaces_button.tsx

@@ -11,6 +11,7 @@ import { MANAGE_SPACES_URL } from '../lib/constants';
 
 interface Props {
   isDisabled?: boolean;
+  className?: string;
   size?: 's' | 'l';
   style?: CSSProperties;
   userProfile: UserProfile;
@@ -26,7 +27,7 @@ export class ManageSpacesButton extends Component<Props, {}> {
     return (
       <EuiButton
         size={this.props.size || 's'}
-        className="manage-spaces-button"
+        className={this.props.className}
         isDisabled={this.props.isDisabled}
         onClick={this.navigateToManageSpaces}
         style={this.props.style}

x-pack/plugins/spaces/public/views/nav_control/components/_spaces_menu.scss

@@ -7,7 +7,11 @@
   overflow-y: auto;
 }
 
-.spcMenu__searchFieldWrapper,
-.spcMenu__manageButtonWrapper {
+.spcMenu__searchFieldWrapper {
   padding: $euiSizeM;
 }
+
+.spcMenu__manageButton {
+  margin: $euiSizeM;
+  width: calc(100% - #{$euiSizeM*2});
+}

x-pack/plugins/spaces/public/views/nav_control/components/spaces_menu.tsx

@@ -134,14 +134,13 @@ export class SpacesMenu extends Component<Props, State> {
 
   private renderManageButton = () => {
     return (
-      <div key="manageSpacesButton" className="spcMenu__manageButtonWrapper">
-        <ManageSpacesButton
-          size="s"
-          style={{ width: `100%` }}
-          userProfile={this.props.userProfile}
-          onClick={this.props.onManageSpacesClick}
-        />
-      </div>
+      <ManageSpacesButton
+        key="manageSpacesButton"
+        className="spcMenu__manageButton"
+        size="s"
+        userProfile={this.props.userProfile}
+        onClick={this.props.onManageSpacesClick}
+      />
     );
   };