Fix behavior of localinstall command

Commit de9643a (first shipped in dnf 4.2.8) changed opts.command
from a list to a simple string, but code in InstallCommand 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 `localinstall` form, since it would no
longer detect that command to restrict search of packages.

Before this commit, this command would (incorrectly) succeed:
  $ dnf localinstall joe

After this commit:
  $ dnf localinstall joe
  Not a valid rpm file path: joe
  Error: Nothing to do.

Closes: #1611
Approved by: m-blaha

dnf/cli/commands/install.py

@@ -74,12 +74,12 @@ def run(self):
         nevra_forms = self._get_nevra_forms_from_command()
 
         self.cli._populate_update_security_filter(self.opts, self.base.sack.query())
-        if self.opts.command == ['localinstall'] and (self.opts.grp_specs or self.opts.pkg_specs):
+        if self.opts.command == 'localinstall' and (self.opts.grp_specs or self.opts.pkg_specs):
             self._log_not_valid_rpm_file_paths(self.opts.grp_specs)
             if self.base.conf.strict:
                 raise dnf.exceptions.Error(_('Nothing to do.'))
         skipped_grp_specs = []
-        if self.opts.grp_specs and self.opts.command != ['localinstall']:
+        if self.opts.grp_specs and self.opts.command != 'localinstall':
             if dnf.base.WITH_MODULES:
                 try:
                     module_base = dnf.module.module_base.ModuleBase(self.base)
@@ -108,10 +108,10 @@ def run(self):
             self._inform_not_a_valid_combination(skipped_grp_specs)
             if self.base.conf.strict:
                 raise dnf.exceptions.Error(_('Nothing to do.'))
-        elif skipped_grp_specs and self.opts.command != ['localinstall']:
+        elif skipped_grp_specs and self.opts.command != 'localinstall':
             self._install_groups(skipped_grp_specs)
 
-        if self.opts.command != ['localinstall']:
+        if self.opts.command != 'localinstall':
             errs = self._install_packages(nevra_forms)
 
         if (len(errs) != 0 or len(err_pkgs) != 0 or error_module_specs) and self.base.conf.strict: