Use fully-qualified Truncate constant

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: myabc

app/components/primer/open_project/border_box/collapsible_header.rb

@@ -22,7 +22,7 @@ class CollapsibleHeader < Primer::Component
             "Box-title"
           )
 
-          Beta::Truncate.new(tag: fetch_or_fallback(TITLE_TAG_OPTIONS, tag, TITLE_TAG_DEFAULT), **system_arguments)
+          Primer::Beta::Truncate.new(tag: fetch_or_fallback(TITLE_TAG_OPTIONS, tag, TITLE_TAG_DEFAULT), **system_arguments)
         }
 
         # Optional count