gRPC + global ConfigureHttpClient error

[JamesNK]

There is now a global ConfigureHttpClient option to configure all clients created by client factory. This feature conflicts with gRPC integration into the factory, which throws an error if the global ConfigureHttpClient is used. See dotnet/extensions#4924 (comment)

Options to improve:

• Add a flag to suppress this error.
• Detect when this configuration is global and automatically don't error.

[iliar-turdushev]

@JamesNK Does the following PR #2448 fixes current issue? Thanks.

[JamesNK]

Yes. Thanks for the heads up.