[DOC] Update doc to reflect thread sampling logic required for tracing integration on

[knylander-grafana]

Update the docs to include this:

Walltime profiling is required to have thread sampling logic changed with the tracing integration on. However, this information is not included in the docs.

In the docs, walltime profiling is only mentioned in the .NET SDK: https://grafana.com/docs/pyroscope/latest/configure-client/language-sdks/dotnet/#dynamic-control

The trace to profiles documentation is on this page: https://grafana.com/docs/pyroscope/latest/configure-client/trace-span-profiles/dotnet-span-profiles/

Tasks:

• Verify the information is correct
• Which config options are useful for this?
• Provide an example in the config option for the tracing integration