Some Azure endpoints have some trouble handling duplicated slashes ('//') in the endpoint's URL

[andras-pinter]

Hey!

I encountered an issue when I wanted to query an AppConfiguration endpoint with the azure_svc_appconfiguration crate.
The generated URL contained a duplicate slash, which confused Azure's AppConfiguration endpoint.

Example:
My base URL: https://some-app-conf.azconfig.io/
The generated request's URL: https://some-app-conf.azconfig.io//keys?api-version=2023-10-01
This resulted in a 404 response. However, if I remove the duplicated slash from the Request, like:
https://some-app-conf.azconfig.io/keys?api-version=2023-10-01
everything just works as expected.

This could be an issue for other Azure REST endpoints as well.
I think some Azure endpoints experiencing some troubles dealing with duplicated slashes in the URL.

I tried with the latest version (0.20.0).

I made a draft Pull Request to solve this problem: #1663