Download file using WebClient

Right now, the only way to download a file from Slack is to do something like this:

import requests
response = requests.get(url_private, headers={"Authorization": f"Bearer {TOKEN}"}, timeout=30)

However, this does not respects the parameters passed to WebClient. We should be able to do something like:

client = WebClient()
response = client.get(url_private)

Or something along those lines.

Category (place an x in each of the [ ])

• slack_sdk.web.WebClient (sync/async) (Web API client)
• slack_sdk.webhook.WebhookClient (sync/async) (Incoming Webhook, response_url sender)
• slack_sdk.models (UI component builders)
• slack_sdk.oauth (OAuth Flow Utilities)
• slack_sdk.socket_mode (Socket Mode client)
• slack_sdk.audit_logs (Audit Logs API client)
• slack_sdk.scim (SCIM API client)
• slack_sdk.rtm (RTM client)
• slack_sdk.signature (Request Signature Verifier)

Requirements

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Beginne damit, die synchronen und asynchronen Implementierungen von slack_sdk.web.WebClient zu lesen und nachzuverfolgen, wie sie Client-Parameter auf Requests anwenden. Prüfe die vorhandenen Tests für den Web API client, sofern vorhanden, und definiere den Abschluss so, dass Dateidownloads über WebClient ermöglicht werden, während die konfigurierten Parameter erhalten bleiben und beide Client-Varianten unterstützt werden.