Improve/verbosify error messages in various ToInteropOptions methods

[adeal]

What was changed

This a small change to make (most of) the ArgumentException messages in OptionsExtensions more verbose. Specifically, this change focuses on errors caused by the absence of a property being set, and includes the name of the options class that it is missing from.

Why?

The various ToInteropOptions(...) methods are the first place where options classes get checked for correctness. Since these are "deeper" in the SDK than what most users are digging into, it can make the error challenging to interpret.

For example, we can look at an error thrown when TargetHost is not set for HttpConnectProxyOptions:

1. The call stack is unrelated to the location where a user might configure these client options, such as Program.cs or Startup.cs, so it can be unclear that this is a user error
2. "TargetHost" is an overloaded property name throughout the SDK, so disambiguating it to HttpConnectProxyOptions would be helpful

Checklist

1. Closes

2. How was this tested:

Not necessary; no functional changes.

5. Any docs updates needed?

None known.

[cretz]

Thanks!