Added required-nested-flatbuffer to monster_test and fixed rust (#6236)

Co-authored-by: Casper Neo <cneo@google.com>

tests/monster_test_generated.js

@@ -1904,11 +1904,36 @@ MyGame.Example.Monster.prototype.mutate_signed_enum = function(value) {
   return true;
 };
 
+/**
+ * @param {number} index
+ * @returns {number}
+ */
+MyGame.Example.Monster.prototype.testrequirednestedflatbuffer = function(index) {
+  var offset = this.bb.__offset(this.bb_pos, 102);
+  return offset ? this.bb.readUint8(this.bb.__vector(this.bb_pos + offset) + index) : 0;
+};
+
+/**
+ * @returns {number}
+ */
+MyGame.Example.Monster.prototype.testrequirednestedflatbufferLength = function() {
+  var offset = this.bb.__offset(this.bb_pos, 102);
+  return offset ? this.bb.__vector_len(this.bb_pos + offset) : 0;
+};
+
+/**
+ * @returns {Uint8Array}
+ */
+MyGame.Example.Monster.prototype.testrequirednestedflatbufferArray = function() {
+  var offset = this.bb.__offset(this.bb_pos, 102);
+  return offset ? new Uint8Array(this.bb.bytes().buffer, this.bb.bytes().byteOffset + this.bb.__vector(this.bb_pos + offset), this.bb.__vector_len(this.bb_pos + offset)) : null;
+};
+
 /**
  * @param {flatbuffers.Builder} builder
  */
 MyGame.Example.Monster.startMonster = function(builder) {
-  builder.startObject(49);
+  builder.startObject(50);
 };
 
 /**
@@ -2634,6 +2659,35 @@ MyGame.Example.Monster.addSignedEnum = function(builder, signedEnum) {
   builder.addFieldInt8(48, signedEnum, MyGame.Example.Race.None);
 };
 
+/**
+ * @param {flatbuffers.Builder} builder
+ * @param {flatbuffers.Offset} testrequirednestedflatbufferOffset
+ */
+MyGame.Example.Monster.addTestrequirednestedflatbuffer = function(builder, testrequirednestedflatbufferOffset) {
+  builder.addFieldOffset(49, testrequirednestedflatbufferOffset, 0);
+};
+
+/**
+ * @param {flatbuffers.Builder} builder
+ * @param {Array.<number>} data
+ * @returns {flatbuffers.Offset}
+ */
+MyGame.Example.Monster.createTestrequirednestedflatbufferVector = function(builder, data) {
+  builder.startVector(1, data.length, 1);
+  for (var i = data.length - 1; i >= 0; i--) {
+    builder.addInt8(data[i]);
+  }
+  return builder.endVector();
+};
+
+/**
+ * @param {flatbuffers.Builder} builder
+ * @param {number} numElems
+ */
+MyGame.Example.Monster.startTestrequirednestedflatbufferVector = function(builder, numElems) {
+  builder.startVector(1, numElems, 1);
+};
+
 /**
  * @param {flatbuffers.Builder} builder
  * @returns {flatbuffers.Offset}