Do not stop spinner on closing window

This prevents UI issue where chat is outputting but spinner is not
spinning until new text is appended. Spinner can spin in background
just fine so let it.

Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

Author: deathbeam

lua/CopilotChat/chat.lua

@@ -241,23 +241,21 @@ function Chat:open(config)
 end
 
 function Chat:close(bufnr)
-  if self.spinner then
-    self.spinner:finish()
+  if not self:visible() then
+    return
   end
 
-  if self:visible() then
-    if self:active() then
-      utils.return_to_normal_mode()
-    end
-
-    if self.layout == 'replace' then
-      self:restore(self.winnr, bufnr)
-    else
-      vim.api.nvim_win_close(self.winnr, true)
-    end
+  if self:active() then
+    utils.return_to_normal_mode()
+  end
 
-    self.winnr = nil
+  if self.layout == 'replace' then
+    self:restore(self.winnr, bufnr)
+  else
+    vim.api.nvim_win_close(self.winnr, true)
   end
+
+  self.winnr = nil
 end
 
 function Chat:focus()