remove dependencies to @theia/json in order to support VS Code JSON language features extensions

[akosyakov]

Right now @theia/json Theia extension is always pulled via @theia/debug extension. We should remove such dependencies to make it possible to replace @theia/json extension by VS Code extension.

cc @thegecko

[thegecko]

RE:
#3657
#3663

Without this dependency, the debug configuration integration in the editor didn't work. Perhaps that UI should have a fallback when @theia/json is missing?

[akosyakov]

Without this dependency, the debug configuration integration in the editor didn't work. Perhaps that UI should have a fallback when @theia/json is missing?

One can always include it explicitly in package.json. We can add a notification please install json extension?

[thegecko]

In the case above it really wasn't clear that this dependency existed and as the UI is 'hidden' in the editor, it wasn't clear there was actually an issue.

IMO, I would prefer to see an error thrown if a required dependency is missing.

[paul-marechal]

Would the debug configuration assistance work with the vscode json extension? IIUC we explicitly register schemas against our JsonSchemaStore component, would this be picked up by the vscode ext?

[akosyakov]

Would the debug configuration assistance work with the vscode json extension? IIUC we explicitly register schemas against our JsonSchemaStore component, would this be picked up by the vscode ext?

We need to test and if not, we should make sure that it does.