luci-proto-openvpn: align askpass parameter with proto handler

the proto handlers look for `askpass` which is a file type param.

Closes #8630

Signed-off-by: David Perez <d4v1dp3@gmail.com>
Signed-off-by: Paul Donald <newtwen+github@gmail.com>

protocols/luci-proto-openvpn/htdocs/luci-static/resources/protocol/openvpn.js

@@ -953,7 +953,7 @@ const openvpnOptions = [
 		tab: 'cryptography',
 		type: form.FileUpload,
 		root_directory: '/etc',
-		name: 'askpass_file',
+		name: 'askpass',
 		label: _('Get certificate password from file before we daemonize')
 	},
 	{