Allow passing "kwargs" to "pkg.list_downloaded" on Zypper (bsc#1140193)

[meaksh]

What does this PR do?

This PR fixes an issue with pkg.list_downloaded function in the Zypper module. This function currently does not accept any kwarg argument, which makes the logic of the pkg.downloaded state to crash.

Given the following example of SLS at /srv/salt/test_pkg.sls:

test_pkg_downloaded:
  pkg.downloaded:
    - name: salt

Running salt-call --local state.apply test_pkg will produce a traceback:

local:
----------
          ID: test_pkg_downloaded
    Function: pkg.downloaded
        Name: salt
      Result: False
     Comment: An exception occurred in this state: Traceback (most recent call last):
                File "/usr/lib/python3.7/site-packages/salt/state.py", line 1939, in call
                  ret = self.states[cdata['full']](*cdata['args'], **cdata['kwargs'])
                File "/usr/lib/python3.7/site-packages/salt/loader.py", line 1982, in wrapper
                  return f(*args, **kwargs)
                File "/usr/lib/python3.7/site-packages/salt/states/pkg.py", line 2068, in downloaded
                  **kwargs)
                File "/usr/lib/python3.7/site-packages/salt/states/pkg.py", line 268, in _find_download_targets
                  cur_pkgs = __salt__['pkg.list_downloaded'](**kwargs)
              TypeError: list_downloaded() got an unexpected keyword argument 'fromrepo'
     Started: 09:20:36.896878
    Duration: 0.843 ms
     Changes:   

Summary for local
------------
Succeeded: 0
Failed:    1
------------
Total states run:     1
Total run time:   0.843 ms

Tests written?

Yes

Commits signed with GPG?

Yes

[meaksh]

Closing in favor of #56490