chore!: remove telemetry API usage (#3815)

# What does this PR do?

remove telemetry as a providable API from the codebase. This includes
removing it from generated distributions but also the provider registry,
the router, etc

since `setup_logger` is tied pretty strictly to `Api.telemetry` being in
impls we still need an "instantiated provider" in our implementations.
However it should not be auto-routed or provided. So in
validate_and_prepare_providers (called from resolve_impls) I made it so
that if run_config.telemetry.enabled, we set up the meta-reference
"provider" internally to be used so that log_event will work when
called.

This is the neatest way I think we can remove telemetry from the
provider configs but also not need to rip apart the whole "telemetry is
a provider" logic just yet, but we can do it internally later without
disrupting users.

so telemetry is removed from the registry such that if a user puts
`telemetry:` as an API in their build/run config it will err out, but
can still be used by us internally as we go through this transition.


relates to #3806

Signed-off-by: Charlie Doern <cdoern@redhat.com>

llama_stack/core/server/server.py

@@ -445,7 +445,7 @@ def create_app() -> StackApp:
         if cors_config:
             app.add_middleware(CORSMiddleware, **cors_config.model_dump())
 
-    if Api.telemetry in impls:
+    if config.telemetry.enabled:
         setup_logger(impls[Api.telemetry])
     else:
         setup_logger(TelemetryAdapter(TelemetryConfig(), {}))