vt730: Bug in CRMEntity->buildSearchQueryForFieldTypes() method.

This method will return a broken query if the module has no fields of the uitype requested.

https://code.vtiger.com/vtiger/vtigercrm/blob/7.3.0H2/data/CRMEntity.php#L2621

As you can see there no test to check if $querycolumnnames (or $entitycolumnnames) actually contains anything. The result is you get a query back like this:

select crmid as id, , $entitycolumnnames as name ...

The way I think to fix this is to check these variables before generating the query and if either are empty then return false.