[fix] do not be over-eager in removing unused CSS for dialog[open] (#7495)

src/compiler/compile/css/Selector.ts

@@ -21,7 +21,8 @@ enum NodeExist {
 }
 
 const whitelist_attribute_selector = new Map([
-	['details', new Set(['open'])]
+	['details', new Set(['open'])],
+	['dialog', new Set(['open'])]
 ]);
 
 export default class Selector {

test/css/samples/attribute-selector-dialog-open/expected.css

@@ -0,0 +1 @@
+dialog[open].svelte-xyz{display:grid}

test/css/samples/attribute-selector-dialog-open/input.svelte

@@ -0,0 +1,7 @@
+<dialog>Hello</dialog>
+
+<style>
+	dialog[open] {
+		display: grid;
+	}
+</style>