bug#70958: 30.0.50; eglot-managed-mode hooks not called on shutdown

[Troy Brown]

The documentation for eglot-managed-mode-hook indicates that the hook
is run after Eglot has started/stopped managing a buffer.  I was
trying to use this to perform setup/teardown of functionality when
this happened, but it appears the registered hooks are never called on
shutdown.  The following is a little test that can be run in a buffer
which has LSP support, to demonstrate the problem.  My expectation is
that "Buffer not managed" is output and the my-eglot-hook-var is
changed to 'not-managed when a shutdown occurs.

--8<---------------cut here---------------start------------->8---
(defun my-eglot-test ()
  (defun my-eglot-hook ()
    (message "my-eglot-hook invoked")
    (if (eglot-managed-p)
        (progn
          (message "Buffer is managed")
          (setq-local my-eglot-hook-var 'managed))
      (message "Buffer not managed")
      (setq-local my-eglot-hook-var 'not-managed)))
  (add-hook 'eglot-managed-mode-hook #'my-eglot-hook)
  (setq-local my-eglot-hook-var 'initial)
  (cl-assert (not (eglot-managed-p)))
  (cl-assert (eq my-eglot-hook-var 'initial))
  (call-interactively #'eglot)
  (cl-assert (eglot-managed-p))
  (cl-assert (eq my-eglot-hook-var 'managed))
  (sleep-for 3) ; wait for server connection
  (call-interactively #'eglot-shutdown)
  (cl-assert (not (eglot-managed-p)))
  (cl-assert (eq my-eglot-hook-var 'not-managed)))
--8<---------------cut here---------------end--------------->8---