### Summary

when i use ansible systemd module, but the result is different between using systemd module and not using systemd module. 


```
 - name: using systemd module
    systemd:
      name: my.service
      state: stopped
      enabled: no
```

```
- name: using just command stop
  command: systemctl stop my.service

- name: using just command disable
  command: systemctl disable my.service
```
In Detail, my.service's killMode is process (KillMode=process), so if i stop my.service, another process in my.service cgroup  are not killed.  but when i use systemd module to stop and disable,  all process in my.service cgroup are killed 

### Issue Type

Bug Report

### Component Name

systemd

### Ansible Version

```console
$ ansible --version
ansible [core 2.11.10] 
  config file = /Users/kakao_ent/cloudms/git_ms/msg-deploy/ansible/ansible.cfg
  configured module search path = ['/Users/kakao_ent/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/kakao_ent/cloudms/git_ms/msg-deploy/ansible/env/lib/python3.7/site-packages/ansible
  ansible collection location = /Users/kakao_ent/.ansible/collections:/usr/share/ansible/collections
  executable location = env/bin/ansible
  python version = 3.7.8 (v3.7.8:4b47a5b6ba, Jun 27 2020, 04:47:50) [Clang 6.0 (clang-600.0.57)]
  jinja version = 3.1.1
  libyaml = True
```


### Configuration

```console
# if using a version older than ansible-core 2.12 you should omit the '-t all'
$ ansible-config dump --only-changed -t all
```


### OS / Environment

Ubuntu 18.04

### Steps to Reproduce

1. not working task
```
 - name: using systemd module
    systemd:
      name: my.service
      state: stopped
      enabled: no
```

2. working task
```
- name: using just command stop
  command: systemctl stop my.service

- name: using just command disable
  command: systemctl disable my.service
```

and the service file attribute have to add like this

`KillMode=process`



### Expected Results

same as summary

### Actual Results

```console
same as summary
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
module.warn('daemon-reload failed, but target is a chroot or systemd is offline. Continuing. Error was: %d / %s' % (rc, err))
            else:
                module.fail_json(msg='failure %d during daemon-reload: %s' % (rc, err))
    
    if module.params['daemon_reexec'] and not module.check_mode:
        (rc, out, err) = module.run_command("%s daemon-reexec" % (systemctl))
        if rc != 0:
            if is_chroot(module) or os.environ.get('SYSTEMD_OFFLINE') == '1':
                module.warn('daemon-reexec failed, but target is a chroot or systemd is offline. Continuing. Error was: %d / %s' % (rc, err))
            else:
                module.fail_json(msg='failure %d during daemon-reexec: %s' % (rc, err))
    if unit:
        found = False
        is_initd = sysv_exists(unit)
        is_systemd = False
        
        (rc, out, err) = module.run_command("%s show '%s'" % (systemctl, unit))
        if rc == 0 and not (request_was_ignored(out) or request_was_ignored(err)):
            
            if out:
                result['status'] = parse_systemctl_show(to_native(out).split('\n'))
                is_systemd = 'LoadState' in result['status'] and result['status']['LoadState'] != 'not-found'
                is_masked = 'LoadState' in result['status'] and result['status']['LoadState'] == 'masked'
                
                if is_systemd and not is_masked and 'LoadError' in result['status']:
                    module.fail_json(msg="Error loading unit file '%s': %s" % (unit, result['status']['LoadError']))
        
        elif err and rc == 1 and 'Failed to parse bus message' in err:
            result['status'] = parse_systemctl_show(to_native(out).split('\n'))
            unit_base, sep, suffix = unit.partition('@')