Make deleting a dynamic field db column optional

[dkelly]

Please could you update DynamicField::deleteField() with an option to keep the table column intact on the database. This is desirable for some things, for example if you are enabling or disabling a feature that makes use of a custom column, and want to keep the data intact when disabling the feature.

I propose updating the function with the following, which has been filed in the Sugar bug tracker under #39776:

    function deleteField($widget, $drop_column = true)
   {
        require_once('modules/DynamicFields/templates/Fields/TemplateField.php');
          
        global $beanList;
        
        if (!($widget instanceof TemplateField)) {
            $field_name         = $widget;
            $widget             = new TemplateField();
            $widget->name       = $field_name;
        }
        
        $object_name = $beanList[$this->module];
        
        if ($object_name == 'aCase')
            $object_name =  'Case';
        
        $GLOBALS['db']->query("DELETE FROM fields_meta_data WHERE id='{$this->module}{$widget->name}'; ");
        
        if($drop_column)
        {
            $sql = $widget->get_db_delete_alter_table( $this->bean->table_name . "_cstm" ) ;
            if (! empty( $sql ) )
            {
                $GLOBALS['db']->query( $sql );
 
                $GLOBALS['log']->debug("deleted column from {$this->bean->table_name}_cstm");
 
            }
        }        
 
        VardefManager::clearVardef();
        VardefManager::refreshVardefs($this->module, $object_name);
        
    }