feat: DIA-2044: Add label config to "import sample data"

[matt-bernstein]

• Warning message pops up when the user has a saved label config for this project, or has typed something into the Label Config page
• samples may contain a label config, and that label config is applied to the project when the data import page is saved.

Rebased on #7206

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[nick-skriabin]

can we put the warning next to the select rather than above it? this way it should keep the layout intact

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