Charts based on Virtual Datasets Names in UTF-8

[butuzov]

Bug description

As title says - one you have multiple charts based on different virtual datasets (named in UTF-8) in your dashboard, you not able to export it propertly as next virtual dataset transforms into ROOT_folder/datasets/-.yaml, which is already choosen.

How to reproduce the bug

I might not really understand how to create everything required by steps, however I hope my explanations are clear.

1. Crete few virtual datasets (more than one) nand give them a non-latin name (initialy was used cirillic)
2. Create charts based on this virtual datasets
3. Create Dashboard and place charts to it.
4. Export Dashboard (via api)
5. Import Exported File to another Superset instance

Observe:

• missing charts / missing datasets
• in addition to missing charts, some charts seams missing for dashboard (like area is gray, but once you update charts it appearse where it belongs.)

Superset version

3.1.1

Additional context

I have solved it locally by adding transliteration for names by useing transliterate package, but it might be not proper way to fix it.

Checklist

• I have searched Superset docs and Slack and didn't find a solution to my problem.
• I have searched the GitHub issue tracker and didn't find a similar bug report.
• I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.