Twenty Twenty-One: Re-add px unit to the admin bar height custom property.

The `px` unit added in [50388] to prevent invalid values when using `calc` functions was inadvertently removed in [50972].

This re-adds the unit to ensure the issue reported in #52564 remains fixed. The same stylelint rule adjustment made in [50388] to `.stylelintrc-css.json` has also been copied over to `stylelintrc.json` file,  which is the configuration file used when linting `.scss` files.

Props ocean90.
See #52624, #52564.

git-svn-id: https://develop.svn.wordpress.org/trunk@50975 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-content/themes/twentytwentyone/.stylelintrc.json

@@ -10,6 +10,7 @@
 		"at-rule-empty-line-before": null,
 		"selector-pseudo-element-colon-notation": null,
 		"number-leading-zero": null,
-		"no-descending-specificity": null
+		"no-descending-specificity": null,
+		"length-zero-no-unit": [true, {"ignore": ["custom-properties"]}]
 	}
 }

src/wp-content/themes/twentytwentyone/assets/css/style-editor.css

@@ -224,7 +224,7 @@
 	--widget--spacing-menu: calc(0.66 * var(--global--spacing-unit));
 
 	/* Admin-bar height */
-	--global--admin-bar--height: 0;
+	--global--admin-bar--height: 0px;
 }
 
 .admin-bar {

src/wp-content/themes/twentytwentyone/assets/sass/01-settings/global.scss

@@ -227,7 +227,7 @@ $baseline-unit: 10px;
 	--widget--spacing-menu: calc(0.66 * var(--global--spacing-unit));
 
 	/* Admin-bar height */
-	--global--admin-bar--height: 0;
+	--global--admin-bar--height: 0px;
 }
 
 .admin-bar {

src/wp-content/themes/twentytwentyone/style-rtl.css

@@ -317,7 +317,7 @@ Twenty Twenty-One is distributed under the terms of the GNU GPL.
 	--widget--spacing-menu: calc(0.66 * var(--global--spacing-unit));
 
 	/* Admin-bar height */
-	--global--admin-bar--height: 0;
+	--global--admin-bar--height: 0px;
 }
 
 .admin-bar {

src/wp-content/themes/twentytwentyone/style.css

@@ -317,7 +317,7 @@ Twenty Twenty-One is distributed under the terms of the GNU GPL.
 	--widget--spacing-menu: calc(0.66 * var(--global--spacing-unit));
 
 	/* Admin-bar height */
-	--global--admin-bar--height: 0;
+	--global--admin-bar--height: 0px;
 }
 
 .admin-bar {