Exclude which-key from layer sync powerline restore

When syncing the configuration layers `SPC f e R`,
don't restore the powerline to the which-key buffer.

CHANGELOG.develop

@@ -917,6 +917,7 @@ Other:
   - Added ranger-mode to golden-ratio-exclude-modes (thanks to Langston Barrett)
   - Fixed evil surround bindings (thanks to Hoyon Mak)
   - Improved Window Manipulation Transient state (thanks to yuhan0)
+  - Exclude which-key from layer sync powerline restore (thanks to Doug Wilson)
 *** Layer changes and fixes
 **** Ansible
 - Improvements:

layers/+spacemacs/spacemacs-modeline/funcs.el

@@ -50,9 +50,11 @@ Return nil if no scale is defined."
     (powerline-reset)))
 
 (defun spacemacs//restore-buffers-powerline ()
-  "Restore the powerline in all buffers."
+  "Restore the powerline in the buffers.
+Excluding which-key."
   (dolist (buffer (buffer-list))
-    (spacemacs//restore-powerline buffer)))
+    (unless (string-match-p "\\*which-key\\*" (buffer-name buffer))
+      (spacemacs//restore-powerline buffer))))
 
 (defun spacemacs//prepare-diminish ()
   (when spaceline-minor-modes-p