### 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
)
    unit = module.params['name']
    if unit is not None:
        for globpattern in (r"*", r"?", r"["):
            if globpattern in unit:
                module.fail_json(msg="This module does not currently support using glob patterns, found '%s' in service name: %s" % (globpattern, unit))
    systemctl = module.get_bin_path('systemctl', True)
    if os.getenv('XDG_RUNTIME_DIR') is None:
        os.environ['XDG_RUNTIME_DIR'] = '/run/user/%s' % os.geteuid()
    
    
    
    if module.params['scope'] != 'system':
        systemctl += " --%s" % module.params['scope']
    if module.params['no_block']:
        systemctl += " --no-block"
    if module.params['force']:
        systemctl += " --force"
    rc = 0
    out = err = ''
    result = dict(
        name=unit,
        changed=False,
        status=dict(),
    )
    
    if module.params['daemon_reload'] and not module.check_mode:
        (rc, out, err) = module.run_command("%s daemon-reload" % (systemctl))
        if rc != 0:
            if is_chroot(module) or os.environ.get('SYSTEMD_OFFLINE') == '1':