fix(sdk): suppress telemetry in SimpleSpanProcessor during export (#3494)

Author: cijothomas

opentelemetry-sdk/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## vNext
 
+- `SimpleSpanProcessor` now suppresses telemetry during export, preventing
+  telemetry-induced-telemetry feedback loops. This aligns with the existing
+  behavior in `BatchSpanProcessor` and `SimpleLogProcessor`.
 - Removed `SimpleConcurrentLogProcessor` and the `experimental_logs_concurrent_log_processor`
   feature flag. The use cases it was designed for (ETW/user_events exporters) are
   better served by modeling those exporters as processors directly.

opentelemetry-sdk/src/trace/span_processor.rs

@@ -172,6 +172,7 @@ impl<T: SpanExporter> SpanProcessor for SimpleSpanProcessor<T> {
             return;
         }
 
+        let _suppress_guard = Context::enter_telemetry_suppressed_scope();
         let result = self
             .exporter
             .lock()