Fix behavior of list-updateinfo and related aliases

Commit de9643a (first shipped in dnf 4.2.8) changed opts.command
from a list to a simple string, but code in UpdateInfoCommand still
handled it as if it was a list.

This broke silently because Python will iterate over a string character
by character, so it never produced a syntax error or an exception that
would be noticed.

But it broke behavior of the `list-updateinfo` form and other aliases,
since it would no longer detect that this alias was used and would use
the default action (`summary`) instead of the one triggered by the alias
(`list`).

Before this commit, this command would incorrectly return the updateinfo
summary only, instead of the full list:
  $ dnf list-updateinfo
  (same as `dnf updateinfo summary` output.)

After this commit:
  $ dnf list-updateinfo
  (same as `dnf updateinfo list` output.)

Closes: #1611
Approved by: m-blaha

dnf/cli/commands/updateinfo.py

@@ -112,9 +112,9 @@ def configure(self):
         self.cli.demands.available_repos = True
         self.cli.demands.sack_activation = True
 
-        if self.opts.command[0] in self.direct_commands:
+        if self.opts.command in self.direct_commands:
             # we were called with direct command
-            self.opts.spec_action = self.direct_commands[self.opts.command[0]]
+            self.opts.spec_action = self.direct_commands[self.opts.command]
         else:
             if self.opts._spec_action:
                 self.opts.spec_action = self.opts._spec_action