Fix usuarios module: resolve PHP 8 warnings and fatal errors

- Fixed undefined array key warnings in usuarios-agregar.php
- Fixed undefined variable warnings (, , )
- Fixed null array offset warnings in db.class.php GetSingle()
- Added default parameter to ValidateMail() in util.class.php
- Fixed PrintErrors() return value for proper error handling
- Fixed integer constraint errors for codigoPostal and sucursalId
- Added missing identificacion and comprobante fields to INSERT query
- Fixed undefined  variable in IsEmailTaked()

modules/usuarios-agregar.php

@@ -7,10 +7,10 @@
 		exit;
 	}
 		
-	if($_POST['type'] == 'saveUsuario'){
-				
+	if(isset($_POST['type']) && $_POST['type'] == 'saveUsuario'){
+
 		$tipo = $_POST['tipo'];
-		$idSuc = $_POST['idSuc'];
+		$idSuc = isset($_POST['idSuc']) ? $_POST['idSuc'] : array();
 				
 		$usuario->setTipo($tipo);
 		$usuario->setNombre($_POST['nombre']);
@@ -109,20 +109,29 @@
 		exit;
 		
 	}
-	
+
+	$nomSuc = '';
+	$info = array('type' => '', 'sucursalId' => '');
+	$post = array('sucursalId' => '');
+
 	if($Usr['type'] == 'gerente'){
 		$sucursal->setSucursalId($Usr['sucursalId']);
 		$nomSuc = $sucursal->GetNameById();
 		$nomSuc = strtoupper(utf8_decode(urldecode($nomSuc)));
 	}
-		
+
 	$sucursales = $sucursal->GetSucursalesByEmpresaId();
-	foreach ($sucursales as $key => $sucursal ){
-		$sucursales[$key]['nombre'] = utf8_decode(urldecode($sucursal['nombre']));
+	$sucursalesFiltered = array();
+	foreach ($sucursales as $item ){
+		if($item){
+			$item['nombre'] = utf8_decode(urldecode($item['nombre']));
+			$sucursalesFiltered[] = $item;
+		}
 	}
-	
+
+	$smarty->assign('info', $info);
+	$smarty->assign('post', $post);
 	$smarty->assign('nomSuc', $nomSuc);
-	$smarty->assign('usuarios', $usuarios);
-	$smarty->assign('sucursales', $sucursales);
+	$smarty->assign('sucursales', $sucursalesFiltered);
 
 ?>