Is your feature request related to a problem? Please describe.
Related to #2254, Since Micro$oft cleverly denies access to its extension marketplace to anything other than its own release of VSCode binaries(How open of you!), open-vsx by eclipse foundation is the alternative extension store for VSCodium and Thea(or self-compiled VSCode). We've been updating Flutter and Dart extensions there, by downloading and uploading manually for a while. But it's a public namespace, anybody can publish a malicious extension too.

Describe the solution you'd like
Please claim the ownership of the namespace Dart-Code and publish both extensions to open-vsx.org.

Describe alternatives you've considered
Downloading .vsix and uploading myself.

Additional context