Describe the bug
When importing vairables and storing them locally, on closing and reopening the plugin the imported variables are lost.

To Reproduce
Steps to reproduce the behavior:

1. Open a Figma file with variables
2. Import the variables using the Tokens Studio plugin
3. Make sure that the tokens are stored locally
4. Close the plugin and reopen the plugin.
5. The imported variables are no longer persent.

Expected behavior
The imported variables should not be lost.

Edge case
If I create a random token after importing the variables the imported tokens are not lost on closing and reopening the plugin.