Update mock_vulnerability_scan fixture from vuln scan tests

[jmv74211]

Related issue
closes #1050

Hi,

This PR makes the following changes:

• Improve mock_vulnerability_scan_fixture from vuln scan tests. Now it uses a mocked agent, and it has been removed a sleep due to it has not to wait to wazuh-modulesd updates the global.db since it is stopped.

• Fix the following error

  test_vulnerability_detector/test_scan_results/test_scan_nvd_feed.py:104: in mock_vulnerability_scan
      control_service('stop', daemon='wazuh-modulesd')
  /usr/local/lib/python3.8/dist-packages/wazuh_testing-4.2.0-py3.8.egg/wazuh_testing/tools/services.py:124: in control_service
      processes = [proc for proc in psutil.process_iter() if daemon in proc.name()]
  /usr/local/lib/python3.8/dist-packages/wazuh_testing-4.2.0-py3.8.egg/wazuh_testing/tools/services.py:124: in <listcomp>
      processes = [proc for proc in psutil.process_iter() if daemon in proc.name()]
  /usr/local/lib/python3.8/dist-packages/psutil/__init__.py:630: in name
      name = self._proc.name()
  /usr/local/lib/python3.8/dist-packages/psutil/_pslinux.py:1516: in wrapper
      return fun(self, *args, **kwargs)
  /usr/local/lib/python3.8/dist-packages/psutil/_pslinux.py:1611: in name
      name = self._parse_stat_file()['name']
  /usr/local/lib/python3.8/dist-packages/psutil/_pslinux.py:1523: in wrapper
      raise NoSuchProcess(self.pid, self._name)
  E   psutil.NoSuchProcess: psutil.NoSuchProcess process no longer exists (pid=83691)
  

Tests

• Proven that tests pass when they have to pass.
• Python codebase satisfies PEP-8 style style guide. pycodestyle --max-line-length=120 --show-source --show-pep8 file.py

Regards.

[spothound]

lgtm