[BUG] JSON array of objects makes the variables page crash when collapsed

[MonsieurNaexec]

Is this a bug in companion itself or a module?

• I believe this to be a bug in companion

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

On the variables page, if a variable contains a json array of objects eg. [ {test: 1} ] , it cannot be collapsed otherwise it causes the page to display an error:
Minified React error #31; visit https://reactjs.org/docs/error-decoder.html?invariant=31&args[]=object%20with%20keys%20%7Btest%7D for the full message or use the non-minified dev environment for full errors and additional helpful warnings.

When visiting the url, the full text is:
Objects are not valid as a React child (found: object with keys {test}). If you meant to render a collection of children, use an array instead.

Seems like the value is somehow fed to React when it shouldn't be

This is irreversible and persists after page refresh. I have to close and restart Companion to reset the variable value

Steps To Reproduce

1. Create a variable $(custom:test)
2. Create a button with a simple action internal: Custom Variable: Set with expression to set the variable with value [{test:1}]
3. Go to the variables page and click on "Collapse variable view"

Expected Behavior

This should make the variable view take less space on screen

Environment (please complete the following information)

- OS: Windows
- Browser: Microsoft Edge
- Companion Version: v3.5.3+7770-stable-df70e20b

Additional context

No response

[MonsieurNaexec]

After some searching, I think it is due to how the value is rendered in CustomVariablesList.tsx line 422.
It expects the variable to be a string and just performs a value?.length > 0 check, but this also hits when the value is an array
A quick solve would be to add a typeof value == "string" where necessary, but fully support complex variables as suggested in #3335 would even be better (altough quite more time consuming)
Another option would be to render the stringified version of the variable value, and maybe also a checkbox to switch between editing raw or json values

I have not tested any of my asumptions above, my conclusions are only based on the analysis of the source code
Not sure I will have any time soon to make a PR but it seems easy enough