[BUG] modules/pkgng.py is missing list_repo_pkgs

[Jsollvander]

Description

In 3007.0 and newer, modules/pkgng.py is missing the function pkg.list_repo_pkgs which is required when running with test=True on FreeBSD.

This is related to the introduction of the feature in #63986.

----------
          ID: ses_exporter
    Function: pkg.latest
      Result: False
     Comment: An exception occurred in this state: Traceback (most recent call last):
                File "/usr/local/lib/python3.11/site-packages/salt/state.py", line 2401, in call
                  ret = self.states[cdata["full"]](
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/loader/lazy.py", line 177, in __call__
                  ret = self.loader.run(run_func, *args, **kwargs)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/loader/lazy.py", line 1480, in run
                  return self._last_context.run(self._run_as, _func_or_method, *args, **kwargs)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/loader/lazy.py", line 1495, in _run_as
                  ret = _func_or_method(*args, **kwargs)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/loader/lazy.py", line 1531, in wrapper
                  return f(*args, **kwargs)
                         ^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/states/pkg.py", line 2847, in latest
                  changes = _get_installable_versions(targets, cur)
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/states/pkg.py", line 1060, in _get_installable_versions
                  explicit_versions = __salt__["pkg.list_repo_pkgs"](*explicit_targets)
                                      ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/loader/context.py", line 106, in __getitem__
                  return self.value()[item]
                         ~~~~~~~~~~~~^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/loader/lazy.py", line 519, in __getitem__
                  _ = super().__getitem__(item)  # try to get the item from the dictionary
                      ^^^^^^^^^^^^^^^^^^^^^^^^^
                File "/usr/local/lib/python3.11/site-packages/salt/utils/lazy.py", line 106, in __getitem__
                  return self._dict[key]
                         ~~~~~~~~~~^^^^^
              KeyError: 'pkg.list_repo_pkgs'
     Started: 17:08:16.092679
    Duration: 273.203 ms
     Changes:
---------- 

I see other people have fixed the same problem for Windows in #67171. So looks like we need to do the same for FreeBSD and friends that are relying on modules/pkgng.py.