[Fix] Exclude localhost from hitting proxies for metadata service requests

[ilia-db]

What changes are proposed in this pull request?

Exclude localhost from hitting proxies for metadata service requests

requests package doesn't do it by default.

Relevant issue: databricks/databricks-vscode#916 (comment)

How is this tested?

Tested manually by running this code against real metadata service of the logged in databricks vscode extension:

import requests
import os

os.environ["HTTP_PROXY"] = "http://test.com"

resp = requests.get("http://127.0.0.1:53468/redacted",
                    timeout=10000,
                    headers={
                        "X-Databricks-Metadata-Version": "1",
                        "X-Databricks-Host": "https://redacted.databricks.com/"
                    }, proxies={"no_proxy": "localhost,127.0.0.1"})

print(resp.text)

The code fails without the no_proxy option

[github-actions]

If integration tests don't run automatically, an authorized user can run them manually by following the instructions below:

Trigger:
go/deco-tests-run/sdk-py

Inputs:

• PR number: 877
• Commit SHA: 12e2d5d797f69263d42f18b9416885137ad8e718

Checks will be approved automatically on success.