File length defined as int32

## Description of the issue

File sizes are defined as int32 in multiple places. This is not enough for larger file sizes.

## Current content
```
"/files/content": {
"options": {
"operationId": "options_files_content",
"summary": "Preflight check before upload",
"tags": [
"Files"
],
"x-box-tag": "uploads",
"description": "Performs a check to verify that a file will be accepted by Box\nbefore you upload the entire file.",
"requestBody": {
"content": {
"application/json": {
"schema": {
"type": "object",
"properties": {
"name": {
"type": "string",
"description": "The name for the file",
"example": "File.mp4"
},
"size": {
"type": "integer",
"format": "int32",
"description": "The size of the file in bytes",
"example": 1024
},
```

## Expected content

Type should be `int64`.