Update document to help on checking if a Docker image is up or outdated

During further investigation of a test failure, the failure may be due to an outdated Docker image, and this document update intends to make it easier to check if that's the case.

Review app affected page: https://qa-docs-check-if-docker-image-is-up-or-outdated.about-src.gitlab.com/handbook/engineering/quality/guidelines/debugging-qa-test-failures/#checking-docker-image