docs: HTML embedding of charts/dashboards without authentication

[lindner-tj]

SUMMARY

Was trying to figure out how to embed dashboards/charts in other websites without SDK, came across this: #28407 I got it working and thought it would be a great addition to the docs.

PR is specifically for docs/docs/configuration/networking-settings.mdx

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

Add frame ancestors to Flask Talisman CSP, restart Superset and embed whatever public dashboard/chart you like

ADDITIONAL INFORMATION

• Has associated issue: Embed charts with iframe without any login. #28407
• Required feature flags:
• Changes UI: docs only
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[sfirke]

This is a very nice addition, something that has been sorely missing from the documentation - thank you!! Let me know if you have questions or disagree with any of my suggestions.

[sfirke]

Thanks @lindner-tj ! Sorry for the slow re-review.

[lindner-tj]

Thanks @lindner-tj ! Sorry for the slow re-review.

@sfirke no worries, thank you for merging :)