docs(picker): popover should not show when open

Per design feedback, the popover should not be showing when the picker
is in the loading state. This updates the Storybook template.

Author: jawinn

components/picker/stories/template.js

@@ -116,6 +116,7 @@ export const Template = ({
 	isOpen = false,
 	isInvalid = false,
 	isDisabled = false,
+	isLoading = false,
 	withSwitch = false,
 	fieldLabelStyle = {},
 	fieldLabelId = "default-picker",
@@ -135,14 +136,15 @@ export const Template = ({
 		isOpen,
 		isInvalid,
 		isDisabled,
+		isLoading,
 		content,
 		labelPosition,
 		ariaLabeledBy: fieldLabelId,
 		...args
 	});
 
 	const popoverMarkup = content.length !== 0 ? Popover({
-		isOpen: isOpen && !isDisabled,
+		isOpen: isOpen && !isDisabled && !isLoading,
 		withTip: false,
 		position: "bottom",
 		isQuiet,