docs: add instructions for stopping Flyte sandbox #7419

Job	Run time
Test Getting started	6m 51s
Check Go Generate (flytecopilot) / Go Generate	1m 59s
flyteadmin integration tests image / build_docker	3m 5s
Check Go Generate (datacatalog) / Go Generate	2m 8s
Check Go Generate (flytectl) / Go Generate	3m 7s
Check Go Generate (flyteadmin) / Go Generate	3m 18s
Lint (flyteadmin) / Run Lint	4m 46s
Dry Run Goreleaser	9m 24s
Check Go Generate (flytepropeller) / Go Generate	3m 23s
Lint (flyteplugins) / Run Lint	4m 6s
Lint (flyteidl) / Run Lint	2m 39s
Lint (flytestdlib) / Run Lint	3m 31s
Lint (flytecopilot) / Run Lint	2m 25s
Lint (datacatalog) / Run Lint	2m 57s
Unit Tests (flytectl) / Run Unit Test	4m 38s
Unit Tests (flyteplugins) / Run Unit Test	4m 53s
Unit Tests (flyteadmin) / Run Unit Test	6m 12s
Lint (flytectl) / Run Lint	3m 46s
Unit Tests (flytestdlib) / Run Unit Test	4m 49s
Build Images / Build & Push Image (datacatalog) / Push to Github Registry	5m 37s
Unit Tests (datacatalog) / Run Unit Test	3m 33s
Build Images / Build & Push Image (flyteadmin) / Push to Github Registry	8m 19s
Build Images / Build & Push Image (flytecopilot) / Push to Github Registry	6m 11s
Build Images / Build & Push Image (flytepropeller) / Push to Github Registry	7m 59s
Unit Tests (flytepropeller) / Run Unit Test	5m 23s
Lint (flytepropeller) / Run Lint	4m 27s
Build Images / Build & Push Image (flytescheduler) / Push to Github Registry	10m 12s
Unit Tests (flytecopilot) / Run Unit Test	3m 9s
Integration Test (flyteadmin) / Integration tests	6m 40s
	2h 19m 27s

Provide feedback