fix: set CovidExplorer boolean URL params to 'false' if omitted
fix: set CovidExplorer boolean URL params to 'false' if omitted

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