breaking aws s3 usage with requests 2.32.0

[kristianelliott80]

requests 2.32.0 introduced a change #6644 that strips double /.

This has introduced an issue where generated presigned urls for s3 keys that start with a / can no longer be used. requests now strips that second / meaning that the key is modified and the signature does not match resulting in 403 errors. We can adjust to remove the leading / in our keys but this may be affecting other users or use cases

Expected Result

To be able to use presigned_urls for s3 keys with leading "/"

Actual Result

URL that was passed was modified resulting in a 403 error response from aws

Reproduction Steps

import requests
import boto3
s3 = boto3.client('s3')
bucket = "bucket"
key = "/key_with_leading_slash.txt"
presigned_url = s3.generate_presigned_url("get_object", Params={'Bucket': bucket, 'Key': key})
requests.get(presigned_url)

System Information

$ python -m requests.help

{
  "chardet": {
    "version": "5.1.0"
  },
  "charset_normalizer": {
    "version": "3.1.0"
  },
  "cryptography": {
    "version": ""
  },
  "idna": {
    "version": "3.4"
  },
  "implementation": {
    "name": "CPython",
    "version": "3.9.6"
  },
  "platform": {
    "release": "10",
    "system": "Windows"
  },
  "pyOpenSSL": {
    "openssl_version": "",
    "version": null
  },
  "requests": {
    "version": "2.32.1"
  },
  "system_ssl": {
    "version": "101010bf"
  },
  "urllib3": {
    "version": "1.26.15"
  },
  "using_charset_normalizer": false,
  "using_pyopenssl": false
}