[Docs] Replace older docker ps command with newer docker container ls command for consistency

Author: michaelkoepf

website/docs/maintenance/observability/quickstart.md

@@ -222,7 +222,7 @@ This recreates `shared-tmpfs` and all data is lost (created tables, running jobs
 Make sure that the modified and added containers are up and running using
 
 ```shell
-docker ps
+docker container ls -a
 ```
 
 4. Now you are all set! You can visit

website/docs/quickstart/flink.md

@@ -140,7 +140,7 @@ This command automatically starts all the containers defined in the Docker Compo
 
 Run 
 ```shell
-docker ps
+docker container ls -a
 ```
 to check whether all containers are running properly.