Make Gnus respect mode-line-buffer-identification-keymap

* lisp/gnus/gnus-group.el (gnus-group-set-mode-line): Use
'propertized-buffer-identification' to buttonise and fontify the
buffer name.
* lisp/gnus/gnus-sum.el (gnus-set-mode-line):
* lisp/gnus/gnus.el (gnus-mode-line-buffer-identification): Adjust
calls to above.
* lisp/gnus/gnus-srvr.el (gnus-browse-foreign-server): Add missing
'gnus-modeline-buffer-identification' call (bug#57977).

lisp/gnus/gnus-group.el

@@ -1717,9 +1717,7 @@ already.  If INFO-UNCHANGED is non-nil, dribble buffer is not updated."
 	  (setq mode-string (substring mode-string 0 (- max-len 4))))
 	(prog1
 	    (setq mode-line-buffer-identification
-		  (gnus-mode-line-buffer-identification
-		   (list (propertize mode-string
-				     'face 'mode-line-buffer-id))))
+		  (gnus-mode-line-buffer-identification (list mode-string)))
 	  (set-buffer-modified-p modified))))))
 
 (defun gnus-group-group-name ()

lisp/gnus/gnus-srvr.el

@@ -829,9 +829,10 @@ claim them."
 	  (erase-buffer))
 	(gnus-browse-mode)
 	(setq mode-line-buffer-identification
-	      (list
-	       (format
-		"Gnus: %%b {%s:%s}" (car method) (cadr method))))
+	      (gnus-mode-line-buffer-identification
+               (list
+	        (format
+		 "Gnus: %%b {%s:%s}" (car method) (cadr method)))))
 	(let ((buffer-read-only nil)
 	      name
 	      (prefix (let ((gnus-select-method orig-select-method))

lisp/gnus/gnus-sum.el

@@ -6207,8 +6207,7 @@ If WHERE is `summary', the summary mode line format will be used."
       ;; Update the mode line.
       (setq mode-line-buffer-identification
 	    (gnus-mode-line-buffer-identification
-	     (list (propertize mode-string
-			       'face 'mode-line-buffer-id))))
+	     (list mode-string)))
       (set-buffer-modified-p t))))
 
 (defun gnus-create-xref-hashtb (from-newsgroup headers unreads)

lisp/gnus/gnus.el

@@ -310,12 +310,15 @@ be set in `.emacs' instead."
   :type 'boolean)
 
 (defun gnus-mode-line-buffer-identification (line)
-  (let ((str (car-safe line)))
+  (let* ((str (car-safe line))
+         (str (if (stringp str)
+                  (car (propertized-buffer-identification str))
+                str)))
     (if (or (not (fboundp 'find-image))
 	    (not (display-graphic-p))
 	    (not (stringp str))
 	    (not (string-match "^Gnus:" str)))
-	line
+	(list str)
       (let ((load-path (append (mm-image-load-path) load-path)))
 	;; Add the Gnus logo.
 	(add-text-properties