Fix the studio not loading, "open in studio" and re-rendering

[philipsens]

I fixed the projectlanding page flickering (re-rendering) by only subscribing to addToast and adding a useMemo in the useToasts store. I find these things stay very tricky so I left some comments to clarify why I did it.

The file structure created issues because it tried to load without any data:

dataProvider={dataProvider!}

I hate the non-null operator being used like this.
Also moved spinner so it is rendered outside of the tree.

When using the "open in studio" button, the studio would open the previous content in a new tab. I fixed it by adding a loadedTabId which makes checking in the canvas-flow.tsx easier.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Matthbo]

Both the flow store and canvas will be quite different with the current issue I'm working on but we'll see how it'll turn out.
If this fixes the current deployment then this is a win for now.

[philipsens]

Both the flow store and canvas will be quite different with the current issue I'm working on but we'll see how it'll turn out. If this fixes the current deployment then this is a win for now.

Yea I was thinking the same. Maybe you could just overwrite it and I could look if its still needed.