Spyder terminal keeps running, even if Spyder is shutdown.

Issue Report Checklist

[x] Searched the issues page for similar reports
[x] Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
[ ] Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
[ ] Could not reproduce inside jupyter qtconsole (if console-related)
[x] Tried basic troubleshooting (if a bug/error)
- [x] Restarted Spyder
- [x] Reset preferences with spyder --reset
- [ ] Reinstalled the latest version of Anaconda
- [ ] Tried the other applicable steps from the Troubleshooting Guide
[x] Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

First of all, thanks for including the spyder-terminal in the standalone installers now as well! However, it seems the underlying server process is not being shut down after Spyder quits. After a few Spyder restarts this leads to multiple python processes listening on different ports at 127.0.0.1 all serving the OS Web Terminal.

This is not only a minor nuisance, but I think can lead to a security incident. If someone exposes a port(range) to the web while the OS Web Terminal is still running on that port (without any indication, unless you check the ports with lsof), I think someone might expose a terminal to the WWW, which is undesirable.

What steps reproduce the problem?

In a terminal run sudo lsof -i -P | grep LISTEN | grep python to see al listening python processes.
Open Spyder
Run sudo lsof -i -P | grep LISTEN | grep python to see al listening python processes.
Close Spyder
Run sudo lsof -i -P | grep LISTEN | grep python to see al listening python processes.

What is the expected output? What do you see instead?

Expected output The list of processes retrieved in step 5 should match the list from step 1. I.e. all python processes started by Spyder should be shut down after closing Spyder.

Actual output A new python process is found in step 5, which was also visible in step 3. If you visit the address that python process listens on (127.0.0.1:<some_port>) you will get the OS Web Terminal, a live terminal into your system.

Paste Traceback/Error Below (if applicable)

N/A

Versions

Spyder version: 5.3.0 None
Python version: 3.9.5 64-bit
Qt version: 5.15.2
PyQt5 version: 5.15.6
Operating System: Darwin 21.4.0

Dependencies

# Mandatory:
applaunchservices >=0.1.7            :  0.2.1 (OK)
atomicwrites >=1.2.0                 :  1.4.0 (OK)
chardet >=2.0.0                      :  4.0.0 (OK)
cloudpickle >=0.5.0                  :  2.0.0 (OK)
cookiecutter >=1.6.0                 :  1.7.3 (OK)
diff_match_patch >=20181111          :  20200713 (OK)
intervaltree >=3.0.2                 :  3.1.0 (OK)
IPython >=7.31.1;<8.0.0              :  7.32.0 (OK)
jedi >=0.17.2;<0.19.0                :  0.18.1 (OK)
jellyfish >=0.7                      :  0.9.0 (OK)
jsonschema >=3.2.0                   :  4.4.0 (OK)
keyring >=17.0.0                     :  23.5.0 (OK)
nbconvert >=4.0                      :  6.4.5 (OK)
numpydoc >=0.6.0                     :  1.2.1 (OK)
parso >=0.7.0;<0.9.0                 :  0.8.3 (OK)
pexpect >=4.4.0                      :  4.8.0 (OK)
pickleshare >=0.4                    :  0.7.5 (OK)
psutil >=5.3                         :  5.9.0 (OK)
pygments >=2.0                       :  2.11.2 (OK)
pylint >=2.5.0                       :  2.13.3 (OK)
pyls_spyder >=0.4.0                  :  0.4.0 (OK)
pylsp >=1.4.1;<1.5.0                 :  1.4.1 (OK)
pylsp_black >=1.2.0                  :  1.2.0 (OK)
qdarkstyle >=3.0.2;<3.1.0            :  3.0.3 (OK)
qstylizer >=0.1.10                   :  0.2.1 (OK)
qtawesome >=1.0.2                    :  1.1.1 (OK)
qtconsole >=5.3.0;<5.4.0             :  5.3.0 (OK)
qtpy >=2.0.1                         :  2.0.1 (OK)
rtree >=0.9.7                        :  0.9.7 (OK)
setuptools >=49.6.0                  :  60.10.0 (OK)
sphinx >=0.6.6                       :  4.5.0 (OK)
spyder_kernels >=2.3.0;<2.4.0        :  2.3.0 (OK)
textdistance >=4.2.0                 :  4.2.2 (OK)
three_merge >=0.1.1                  :  0.1.1 (OK)
watchdog >=0.10.3                    :  2.1.7 (OK)
zmq >=17                             :  22.3.0 (OK)

# Optional:
cython >=0.21                        :  0.29.28 (OK)
matplotlib >=3.0.0                   :  3.5.1 (OK)
numpy >=1.7                          :  1.22.3 (OK)
pandas >=1.1.1                       :  1.4.1 (OK)
scipy >=0.17.0                       :  1.8.0 (OK)
sympy >=0.7.3                        :  1.10.1 (OK)

# Spyder plugins:
spyder_terminal.terminalplugin 1.2.2 :  1.2.2 (OK)

spyder-ide / spyder-terminal