[TS] Fix generation of struct members in object api (#7148)

* Fix C/C++ Create<Type>Direct with sorted vectors

If a struct has a key the vector has to be sorted. To sort the vector
you can't use "const".

* Changes due to code review

* Improve code readability

* Add generate of JSON schema to string to lib

* option indent_step is supported

* Remove unused variables

* Fix break in test

* Fix style to be consistent with rest of the code

* [TS] Fix reserved words as arguments (#6955)

* [TS] Fix generation of reserved words in object api (#7106)

* [TS] Fix generation of object api

* [TS] Fix MakeCamel -> ConvertCase

* [TS] Add test for struct of struct of struct

* Update generated files

* Add missing files

* [TS] Fix query of null/undefined fields in object api

tests/my-game/example/struct-of-structs.ts

@@ -77,12 +77,12 @@ constructor(
 
 pack(builder:flatbuffers.Builder): flatbuffers.Offset {
   return StructOfStructs.createStructOfStructs(builder,
-    (this.a === null ? 0 : this.a.id!),
-    (this.a === null ? 0 : this.a.distance!),
-    (this.b === null ? 0 : this.b.a!),
-    (this.b === null ? 0 : this.b.b!),
-    (this.c === null ? 0 : this.c.id!),
-    (this.c === null ? 0 : this.c.distance!)
+    (this.a?.id ?? 0),
+    (this.a?.distance ?? 0),
+    (this.b?.a ?? 0),
+    (this.b?.b ?? 0),
+    (this.c?.id ?? 0),
+    (this.c?.distance ?? 0)
   );
 }
 }