[FEATURE] Improve testing in panels (observability dashboards with saved object)

[joshuali925]

Is your feature request related to a problem?
Observability is missing tests and does not have good coverage, PRs like #419 does not have tests

When observability dashboards were added, they were duplicated files of the old panels components. The old ones have tests but new ones do not, https://github.com/opensearch-project/dashboards-observability/blob/2.7/public/components/custom_panels/panel_modules/visualization_flyout/__tests__/visualization_flyout.test.tsx

What solution would you like?
Add tests for the new observability dashboards component under https://github.com/opensearch-project/dashboards-observability/tree/2.7/public/components/custom_panels/panel_modules/

What alternatives have you considered?
A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?
Add any other context or screenshots about the feature request here.