chore: optimize `get_amount_class_specificity_increased` (#9853)

* Optimaze

* pnpm format

---------

Co-authored-by: Mike <prince-poley@yandex.ru>

packages/svelte/src/compiler/phases/2-analyze/css/Selector.js

@@ -193,13 +193,7 @@ export default class Selector {
 	}
 
 	get_amount_class_specificity_increased() {
-		let count = 0;
-		for (const block of this.blocks) {
-			if (block.should_encapsulate) {
-				count++;
-			}
-		}
-		return count;
+		return this.blocks.filter((block) => block.should_encapsulate).length;
 	}
 }