remove zlavomat const dependency in invoice button component

remp/crm#1068
+ separate zlavomat invoice message to its own widget

src/components/InvoiceButton/invoice_button.latte

@@ -25,9 +25,7 @@
 	   <a target="_blank" class="btn btn-sm btn-primary" href="{plink :Invoices:Invoices:DownloadInvoice $payment->id}"><i class="fa fa-download"></i> {_invoices.frontend.invoice_button.download}</a>
 	{else}
 		{if $payment->user->invoice == true && !$payment->user->disable_auto_invoice && $paymentInvoicable}
-			{if $payment->payment_gateway->code === Crm\ZlavomatModule\Gateways\Zlavomat::GATEWAY_CODE}
-				<span class="label label-info">Faktúru nájdete vo svojom Zľavomat konte</span>
-			{elseif !$payment->paid_at}
+			{if !$payment->paid_at}
 				<span class="alert alert-danger"><i class="fa fa-warning"></i> {_invoices.frontend.invoice_button.system_error}</span>
 			{elseif (clone $payment->paid_at)->modify('+15 days') > new DateTime('now')}
 				<a target="_blank" class="btn btn-sm btn-primary" href="{plink :Invoices:Invoices:DownloadInvoice $payment->id}"><i class="fa fa-magic"></i> {_invoices.frontend.invoice_button.generate}</a>