Add list target type support to the scan roster.

[DmitryKuzmenko]

What does this PR do?

A small change for scan roster type to make salt-ssh able to address a list of minions.

What issues does this PR fix or reference?

Fixes #52675

Previous Behavior

The tgt_type argument was ignored in the scan roster implementation.

New Behavior

If tgt_type is list (-L command line argument) the target treated as a list of addresses. In other cases works as before. Now it's possible to address a list as the following:

$ ./scripts/salt-ssh --user=dimm --priv=/home/dimm/.ssh/id_rsa --roster=scan -L '127.0.0.1,127.0.0.2' test.ping
127.0.0.1:
    True
127.0.0.2:
    True

Tests written?

No

Commits signed with GPG?

Yes

[dwoz]

@DmitryKuzmenko Are there tests for this?

[DmitryKuzmenko]

There is no any test for the scan roster at all. I've made this change just because to make it was faster than describing why it's not working. I'll look what can I do about a test.

[DmitryKuzmenko]

@dwoz test is here. Could you please re-review this?