[BUG] pkg.installed with sources re-downloads every time

Description
Using pkg.installed on Debian with sources to install a .deb fetches over https results in re-downloading the same file every run.

Setup
Reproducible with an empty minion config and basic SLS (as /tmp/install.sls):

sops_package:
  pkg.installed:
    - sources:
      - sops: https://github.com/mozilla/sops/releases/download/v3.6.1/sops_3.6.1_amd64.deb

Steps to Reproduce the behavior

The sops package is already installed:

# salt-call --local pkg.version sops
local:
    3.6.1

And the file is already in the cache:

 # ls -l /var/cache/salt/minion/extrn_files/github.com/mozilla/sops/releases/download/v3.6.1/sops_3.6.1_amd64.deb 
-rw-r--r-- 1 root root 13135134 Jan  6 16:09 /var/cache/salt/minion/extrn_files/github.com/mozilla/sops/releases/download/v3.6.1/sops_3.6.1_amd64.deb

But running the state causes a re-download:

# salt-call --local --log-level debug state.template /tmp/install.sls
[...]
[INFO    ] Running state [sops_package] at time 16:38:19.150264
[INFO    ] Executing state pkg.installed for [sops_package]
[INFO    ] Executing command ['dpkg-query', '--showformat', '${Status} ${Package} ${Version} ${Architecture}', '-W'] in directory '/home/satwell'
[DEBUG   ] LazyLoaded roots.envs
[DEBUG   ] Could not LazyLoad roots.init: 'roots.init' is not available.
[DEBUG   ] Requesting URL https://github.com/mozilla/sops/releases/download/v3.6.1/sops_3.6.1_amd64.deb using GET method
[DEBUG   ] Using backend: tornado
[INFO    ] Executing command ['dpkg', '-I', '/var/cache/salt/minion/extrn_files/github.com/mozilla/sops/releases/download/v3.6.1/sops_3.6.1_amd64.deb'] in directory '/home/satwell'
[INFO    ] All specified packages are already installed
[INFO    ] Completed state [sops_package] at time 16:38:23.480707 (duration_in_ms=4330.451)
[DEBUG   ] File /var/cache/salt/minion/accumulator/140577000434176 does not exist, no need to cleanup
[DEBUG   ] LazyLoaded highstate.output
local:
----------
          ID: sops_package
    Function: pkg.installed
      Result: True
     Comment: All specified packages are already installed
     Started: 16:38:19.150256
    Duration: 4330.451 ms
     Changes:   

Summary for local
------------
Succeeded: 1
Failed:    0
------------
Total states run:     1 
Total run time:   4.330 s

Expected behavior

Because I've specified the name of a package that's already installed, I wouldn't expect the state do anything. But even if it does make sense to check the package name/version against the specified .deb file, I'd expect salt to use the file already in the cache rather than re-downloading.

Versions Report

Salt Version:        
          Salt: 3002.2                                                                         
  
Dependency Versions:
          cffi: 1.14.4                                                                         
      cherrypy: Not Installed                                                                  
      dateutil: 2.8.1                          
     docker-py: 4.1.0                          
         gitdb: Not Installed                                                                  
     gitpython: Not Installed                                                                  
        Jinja2: 2.11.2                                                                         
       libgit2: Not Installed                                                                  
      M2Crypto: Not Installed                                                                  
          Mako: 1.1.3
       msgpack: 1.0.0                          
  msgpack-pure: Not Installed                  
  mysql-python: Not Installed                  
     pycparser: 2.20                           
      pycrypto: 2.6.1                          
  pycryptodome: 3.9.7
        pygit2: Not Installed                                                                  
        Python: 3.9.1 (default, Dec  8 2020, 07:51:42)                                         
  python-gnupg: 0.4.6                          
        PyYAML: 5.3.1
         PyZMQ: 20.0.0 
         smmap: Not Installed                  
       timelib: Not Installed                  
       Tornado: 4.5.3
           ZMQ: 4.3.3
            
System Versions:                               
          dist: debian testing bullseye
        locale: utf-8                          
       machine: x86_64                         
       release: 5.9.0-4-amd64      
        system: Linux
       version: Debian GNU/Linux testing bullseye                                              
  

Start with the pkg.installed entry point and the /tmp/install.sls reproduction on Debian, then trace how a sources URL is resolved against the minion cache. Verify repeated runs do not request the cached .deb again while preserving the already-installed result, and add or update coverage for this behavior if the relevant tests are located.