Helpers: Fix dumpSql() for bool parameters

[RiKap]

• bug fix
• BC break? no

This is just UI bug fix.
I found that Helpers::dumpSql() has problem with bool parameters.
Bool parameters are processed in last step and casted to (string).
Problem is that (string) FALSE is empty string and not 0.
Because of that is dumpSql() able to generate invalid sql like this:

WHERE (`user`.`deleted` = OR `user`.`deleted` IS NULL)

instead of valid:

WHERE (`user`.`deleted` = 0 OR `user`.`deleted` IS NULL)

[dg]

Thanks