Adding Authorization header for HEAD requests

[razvancicu]

Relevant telegraf.conf

n/a

Logs from Telegraf

telegraf-1  | 2025-02-24T10:54:24Z E! Last-Modified header not found, stopping the watcher for http://<remote-URL-config>

System info

telegraf:1.31

Docker

No response

Steps to reproduce

1. Create custom app for telegraf config;
2. Start Telegraf server with the following parameters: --config <remote-URL-config> --config-url-watch-interval 3m --debug

Expected behavior

Send HEAD requests with Authorization: Token <token> on the interval refresh and check if something is modified (Last-Modified header)

Actual behavior

Telegraf won't see the Last-Modified header in the HEAD requests due to missing Authorization: Token <token> header.

Additional info

No response

[srebhan]

@razvancicu please test the binary in PR #16546, available as soon as CI finished the tests, and let me know if this fixes the issue!