[Docs]: Security considerations for context propagation

[svrnm]

What needs to be changed?

via @Kielek:

I think that it is worth to mention some security best practices, like considering if the users should allow to propagate traces/baggages from the external services/should be dropped in some cases.

I recently updated the context propagation page, but didn't get to incorporate that feedback, will create a follow up PR accordingly.

Name + path of the page

https://opentelemetry.io/docs/concepts/context-propagation/

Additional context

No response