[BUG] modules.ebuildpkg.installed does not honor the 'slot' argument when called from state.pkg.installed

Description
The modules.ebuildpkg.installed module function has an extra argument slot that installs the latest available version in the specified slot. According to the documentation it is ignored if pkgs or sources or version arguments are passed to the function. However, when the function is called from the states.pkg.installed state function, the slot argument is ignored, because the states.pkg.installed state function calls the module function with the pkgs argument - even for single package states. See the additional context section for details.

I am not sure whether this is an issue with the implementation of modules.ebuildpkg.installed or states.pkg.installed.

Setup
Gentoo box running salt and the following SLS file.

postgresql:
  pkg.installed:
    - name: dev-db/postgresql
    - slot: 10

Steps to Reproduce the behavior
The issue can be reproduced by executing the SLS file mentioned above or by running the following command:

sudo salt-call --local --log-level=debug state.single pkg.installed dev-db/postgresql slot=10 refresh=False

Notice that the name argument is set to None, while the pkgs argument is passed in with one item equal to the package name.

[DEBUG   ] Called modules.pkg.install: {'name': None, 'refresh': False, 'pkgs': [{'dev-db/postgresql': None}], 'sources': None, 'kwargs': {'version': None, 'skip_verify': False, 'reinstall': False, 'normalize': True, 'update_holds': False, 'ignore_epoch': None, 'saltenv': 'base', 'allow_updates': False}, 'binhost': None}
...
[INFO    ] Executing command ['emerge', '--ask', 'n', '--quiet', 'dev-db/postgresql'] in directory '/root'

Expected behavior
The package should be installed with the desired slot version. In this particular case, the expectations is to install dev-db/postgresql:10.

[INFO    ] Executing command ['emerge', '--ask', 'n', '--quiet', 'dev-db/postgresql:10'] in directory '/root'

Versions Report

Salt Version:
           Salt: 3001.1
 
Dependency Versions:
           cffi: 1.14.0
       cherrypy: Not Installed
       dateutil: Not Installed
      docker-py: Not Installed
          gitdb: Not Installed
      gitpython: Not Installed
         Jinja2: 2.11.2
        libgit2: 1.0.1
       M2Crypto: Not Installed
           Mako: Not Installed
   msgpack-pure: Not Installed
 msgpack-python: 1.0.0
   mysql-python: Not Installed
      pycparser: 2.20
       pycrypto: 3.9.8
   pycryptodome: 3.9.8
         pygit2: 1.2.1
         Python: 3.8.5 (default, Sep 17 2020, 21:17:31)
   python-gnupg: Not Installed
         PyYAML: 5.3.1
          PyZMQ: 19.0.1
          smmap: Not Installed
        timelib: Not Installed
        Tornado: 4.5.3
            ZMQ: 4.3.2
 
System Versions:
           dist: gentoo 2.7 
         locale: utf-8
        machine: x86_64
        release: 5.4.64
         system: Linux
        version: Gentoo 2.7

Additional context

State function packing the name argument into a pkgs array.
https://github.com/saltstack/salt/blob/e941aa8fd207bb2addd1caa5ffe26cd9ae966095/salt/states/pkg.py#L1685-L1692

Module function not executing due to pkgs being set.
https://github.com/saltstack/salt/blob/e941aa8fd207bb2addd1caa5ffe26cd9ae966095/salt/modules/ebuildpkg.py#L676-L687

Start with the referenced state-packing code in salt/states/pkg.py around lines 1685-1692 and the slot-handling logic in salt/modules/ebuildpkg.py around lines 676-687. Reproduce the issue with the supplied state.single command on Gentoo, then trace how a single package and slot reach the module. Done means the state honors slot=10 and invokes emerge with dev-db/postgresql:10, with coverage for the affected path.