perf(ivy): avoid memory allocation in the isAnimationProp check (#32997)

Accessing a string's character at index allocates a new, single character string.
A better (faster) check is to use `charCodeAt` that doesn't trigger allocation.

This simple change speeds up the element_text_create benchmark by ~7%.

PR Close #32997

packages/core/src/render3/util/attrs_utils.ts

@@ -100,8 +100,9 @@ export function isNameOnlyAttributeMarker(marker: string | AttributeMarker | Css
       marker === AttributeMarker.I18n;
 }
 
-export const ANIMATION_PROP_PREFIX = '@';
-
 export function isAnimationProp(name: string): boolean {
-  return name[0] === ANIMATION_PROP_PREFIX;
+  // Perf note: accessing charCodeAt to check for the first character of a string is faster as
+  // compared to accessing a character at index 0 (ex. name[0]). The main reason for this is that
+  // charCodeAt doesn't allocate memory to return a substring.
+  return name.charCodeAt(0) === 64;  // @
 }