docs(core): fix typo in decorators.ts relating to the use of Object.defineProperty. (angular#37369)

Previously there was a typo in a comment within the PropDecorator function relating to and justifying the use of Object.defineProperty. This PR clears up the wording that comment

PR Close angular#37369

Author: AleksanderBodurri

packages/core/src/util/decorators.ts

@@ -153,8 +153,8 @@ export function makePropDecorator(
 
       function PropDecorator(target: any, name: string) {
         const constructor = target.constructor;
-        // Use of Object.defineProperty is important since it creates non-enumerable property which
-        // prevents the property is copied during subclassing.
+        // Use of Object.defineProperty is important because it creates a non-enumerable property
+        // which prevents the property from being copied during subclassing.
         const meta = constructor.hasOwnProperty(PROP_METADATA) ?
             (constructor as any)[PROP_METADATA] :
             Object.defineProperty(constructor, PROP_METADATA, {value: {}})[PROP_METADATA];