Default enable AST validation in optimizers

PiperOrigin-RevId: 964184247

Author: l46kok

optimizer/src/main/java/dev/cel/optimizer/CelOptimizerOptions.java

@@ -44,7 +44,7 @@ public abstract static class Builder {
 
   /** Returns a new options builder with recommended defaults pre-configured. */
   public static Builder newBuilder() {
-    return new AutoValue_CelOptimizerOptions.Builder().enableAstValidation(false);
+    return new AutoValue_CelOptimizerOptions.Builder().enableAstValidation(true);
   }
 
   CelOptimizerOptions() {}