What's Changed

• Ensure mermaid.min.js is cached properly between loads of the editor by @knolleary in https://github.com/node-red/node-red/pull/4817
• Guard against undefined sessions in multiplayer by @knolleary in https://github.com/node-red/node-red/pull/4816
• Allow auth cookie name to be customised by @knolleary in https://github.com/node-red/node-red/pull/4815
• Fix node validation if the property is not required by @GogoVega in https://github.com/node-red/node-red/pull/4812
• Clean up orphaned editors by @Steve-Mcl in https://github.com/node-red/node-red/pull/4821
• Improve the editor's French translations by @GogoVega in https://github.com/node-red/node-red/pull/4824
• Use a more subtle border on the header by @bonanitech in https://github.com/node-red/node-red/pull/4818
• Bump for 4.0.2 by @knolleary in https://github.com/node-red/node-red/pull/4825

Full Changelog: https://github.com/node-red/node-red/compare/4.0.1...4.0.2