Disable observability by default

Signed-off-by: Mihai Criveti <crivetimihai@gmail.com>

Author: crivetimihai

.env.example

@@ -353,7 +353,7 @@ PLUGINS_ENABLED=false
 #####################################
 
 # Master switch for observability (true/false)
-OTEL_ENABLE_OBSERVABILITY=true
+OTEL_ENABLE_OBSERVABILITY=false
 
 # Service identification
 OTEL_SERVICE_NAME=mcp-gateway