fix(admin): prevent crash when legacy config has more `selectedData` than `dimensions`
fix(admin): prevent crash when legacy config has more `selectedData` than `dimensions`

owid/owid-grapher,OurWorldInData/owid-grapher,owid/owid-grapher,OurWorldInData/owid-grapher,OurWorldInData/owid-grapher,owid/owid-grapher,owid/owid-grapher,OurWorldInData/owid-grapher,owid/owid-grapher,OurWorldInData/owid-grapher