chore(Popover): Move Popover component css module feature flag to staff (#5391)

* Move Popover to staff

* Create soft-fishes-tell.md

Author: jonrohan

.changeset/soft-fishes-tell.md

@@ -0,0 +1,5 @@
+---
+"@primer/react": patch
+---
+
+Move Popover component css module feature flag to staff

packages/react/src/Popover/Popover.tsx

@@ -32,7 +32,7 @@ type StyledPopoverProps = {
   open?: boolean
 } & SxProp
 
-const CSS_MODULES_FLAG = 'primer_react_css_modules_team'
+const CSS_MODULES_FLAG = 'primer_react_css_modules_staff'
 
 const StyledPopover = styled.div.attrs<StyledPopoverProps>(({className, caret = 'top'}) => {
   return {