[FEATURE REQ] Switch to .NET 10 SchemaURL instead of `az.schema_url` when possible

[lmolkova]

Library name

Azure.Core

Please describe the feature.

Use Formally defined OTel schema url introduced in dotnet/runtime#113034 instead of custom az.schema_url attribute on .NET 10+.

Using reflection would be challenging (due to AOT), so we might need to wait until we can take dependency on the corresponding DiagnosticSource version (which ships out of band, but we still update it very slowly).

[jsquire]

@m-redding: Would you please take a look at this when you start looking into OTel for SCM?

[m-redding]

@lmolkova System.Diagnostics.DiagnosticSource is built into the runtime in .NET6+ so we remove the dependency on that package in those targets. I think we should be able to do this once Azure.Core adds a net10.0 target.