nginx preserve upstream header values, fix ip

[kspearrin]

Type of change

- [x] Bug fix
- [ ] New feature development
- [ ] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [ ] Other

Objective

Resolves #2500

Fix improper protocol and host header from persisting across proxy jumps.

Also, remove X-Real-IP header from being evaluated for GetIpAddress since it will always be the value of the last connecting client, which could be a proxy whenever there is a chain of multiple proxies. X-Forwarded-For will properly chain proxy IP addresses in a CSV string, and ASP.NET Core will load the correct value in httpContext.Connection.RemoteIpAddress.

Code changes

• proxy.conf: Null coalesce previously set header values and default back to standard values.
• CoreHelpers.cs: Remove X-Real-IP from being evaluated from self hosted servers for client ip address.

Before you submit

• Please check for formatting errors (dotnet format --verify-no-changes) (required)
• If making database changes - make sure you also update Entity Framework queries and/or migrations
• Please add unit tests where it makes sense to do so (encouraged but not required)
• If this change requires a documentation update - notify the documentation team
• If this change has particular deployment requirements - notify the DevOps team

[MGibson1]

C# looks good, but I'd like @bitwarden/dept-devops to get involved on nginx config. That is beyond my experience, but looks right 🤷

[devmsv]

Hi I,m still facing issue #2500 with 2024.2.3
is this merged or should I use :dev?