fix: update etcd image to bitnamilegacy/etcd:3.5 (#3224)

The Bitnami etcd image (bitnami/etcd:3.5) is deprecated and no longer available in Docker Hub. 
Updated the reference in e2e/server/docker-compose.common.yml to use bitnamilegacy/etcd:3.5 instead. 
This resolves the dev container build failure mentioned in issue #3220.

Author: Gurleen-kansray

e2e/server/docker-compose.common.yml

@@ -27,7 +27,8 @@ services:
       - apisix
 
   etcd:
-    image: bitnami/etcd:3.5
+    image: bitnamilegacy/etcd:3.5
+
     restart: always
     volumes:
       - etcd_data:/bitnami/etcd