fix(plugin): apply first HELM_PLUGINS directory to OCI installs

OCI installs should also target the first directory in HELM_PLUGINS when a list is configured, matching base.Path().

Signed-off-by: Yuhui Luo <92632263+lyh7c00@users.noreply.github.com>

internal/plugin/installer/oci_installer.go

@@ -195,7 +195,7 @@ func (i OCIInstaller) Path() string {
 	if i.Source == "" {
 		return ""
 	}
-	return filepath.Join(i.settings.PluginsDirectory, i.PluginName)
+	return filepath.Join(i.pluginsDir(), i.PluginName)
 }
 
 // extractTarGz extracts a gzipped tar archive to a directory