bug report GUI: guard against `raco pkg show' errors

Various things can go wrong with `raco pkg show', including
permission errors or lock conflicts.

Merge to v5.3.2
(cherry picked from commit d2ce3f714b)

collects/help/private/bug-report-controls.rkt

@@ -446,7 +446,9 @@
   
   (define planet2-info-sp (open-output-string))
   (parameterize ([current-output-port planet2-info-sp])
-    (planet2:show))
+    (with-handlers ([exn:fail? (lambda (exn)
+                                 (printf "ERROR:\n~a" (exn-message exn)))])
+      (planet2:show)))
   (send (send planet2-info get-editor)
         insert
         (get-output-string planet2-info-sp))