fix: do not mark _defineProperty as pure in build output

Fixes #29145

Author: jsaguet

packages/angular/build/src/tools/babel/plugins/pure-toplevel-functions.ts

@@ -59,6 +59,11 @@ export default function (): PluginObj {
           return;
         }
 
+        // Do not annotate _defineProperty function as it is not pure.
+        if (callee.isIdentifier() && callee.node.name === '_defineProperty') {
+          return;
+        }
+
         annotateAsPure(path);
       },
       NewExpression(path) {

packages/angular/build/src/tools/babel/plugins/pure-toplevel-functions_spec.ts

@@ -130,6 +130,18 @@ describe('pure-toplevel-functions Babel plugin', () => {
     `),
   );
 
+  it(
+    'does not annotate _defineProperty function',
+    testCaseNoChange(`
+      class LanguageState {}
+      _defineProperty(
+        LanguageState,
+        'property',
+        'value'
+      );
+    `),
+  );
+
   it(
     'does not annotate object literal methods',
     testCaseNoChange(`