Inconsistent instructions for specifying proxy environment variable values

### Type of issue

Typo

### Description

This page (https://learn.microsoft.com/en-us/dotnet/azure/sdk/configure-proxy?tabs=cmd#configure-using-environment-variables) states that the proxy server URL may be https as well as http and has examples of both. However, the page https://learn.microsoft.com/en-us/dotnet/fundamentals/networking/http/httpclient#configure-an-http-proxy states: "The URL must start with http, not https". Which is correct? Obviously only one can be, so one of these pages needs a correction applied.

### Page URL

https://learn.microsoft.com/en-us/dotnet/azure/sdk/configure-proxy?tabs=cmd#configure-using-environment-variables

### Content source URL

https://github.com/dotnet/docs/blob/main/docs/azure/sdk/configure-proxy.md

### Document Version Independent Id

a9783c6f-6790-61a2-07f8-ac5241cf58a0

### Platform Id

1b773992-e775-3d3e-282d-7b1b8d408932

### Article author

@alexwolfmsft

### Metadata

* ID: 61b7d077-a4a8-46df-e27e-b98b3ae4ff93
* PlatformId: 1b773992-e775-3d3e-282d-7b1b8d408932
* Service: **dotnet-azure**

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