Log OTel init failures instead of silently swallowing them

Use fprintf(stderr, ...) directly in the catch block — no need for
a helper function when there's only one call site.

Author: iskakaushik

src/export/otel_exporter.cc

@@ -440,7 +440,8 @@ bool OTelExporter::EstablishNewConnection() {
     logger = log_provider->GetLogger("pg_stat_ch", "pg_stat_ch_logs");
 
     return true;
-  } catch (const std::exception&) {
+  } catch (const std::exception& e) {
+    fprintf(stderr, "pg_stat_ch: OTel init failed: %s\n", e.what());
     return false;
   }
 }