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/my_game/example/long_enum_generated.rs

@@ -0,0 +1,63 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+#[allow(non_upper_case_globals)]
+mod bitflags_long_enum {
+  flatbuffers::bitflags::bitflags! {
+    #[derive(Default)]
+    pub struct LongEnum: u64 {
+      const LongOne = 2;
+      const LongTwo = 4;
+      const LongBig = 1099511627776;
+    }
+  }
+}
+pub use self::bitflags_long_enum::LongEnum;
+
+impl<'a> flatbuffers::Follow<'a> for LongEnum {
+  type Inner = Self;
+  #[inline]
+  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+    let b = unsafe {
+      flatbuffers::read_scalar_at::<u64>(buf, loc)
+    };
+    unsafe { Self::from_bits_unchecked(b) }
+  }
+}
+
+impl flatbuffers::Push for LongEnum {
+    type Output = LongEnum;
+    #[inline]
+    fn push(&self, dst: &mut [u8], _rest: &[u8]) {
+        unsafe { flatbuffers::emplace_scalar::<u64>(dst, self.bits()); }
+    }
+}
+
+impl flatbuffers::EndianScalar for LongEnum {
+  #[inline]
+  fn to_little_endian(self) -> Self {
+    let b = u64::to_le(self.bits());
+    unsafe { Self::from_bits_unchecked(b) }
+  }
+  #[inline]
+  #[allow(clippy::wrong_self_convention)]
+  fn from_little_endian(self) -> Self {
+    let b = u64::from_le(self.bits());
+    unsafe { Self::from_bits_unchecked(b) }
+  }
+}
+
+impl<'a> flatbuffers::Verifiable for LongEnum {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    u64::run_verifier(v, pos)
+  }
+}
+
+impl flatbuffers::SimpleToVerifyInSlice for LongEnum {}