Fix 64-bit numeric enum values in typescript (#7135)

* Fix 64-bit default numeric enum values in typescript

If you had a default value that wasn't a valid enum value (e.g., a zero
if you used a bit_flag setting, like you get with AdvancedFeatures
in reflection.fbs), we weren't using BigInt.

* Run generate_code.py

* [DART] Handle deprecated fields & invalid enum defaults

* Update .NET test

tests/monster_test_serialize/mod.rs

@@ -7,6 +7,8 @@ pub mod my_game {
     pub use self::color_generated::*;
     mod race_generated;
     pub use self::race_generated::*;
+    mod long_enum_generated;
+    pub use self::long_enum_generated::*;
     mod any_generated;
     pub use self::any_generated::*;
     mod any_unique_aliases_generated;