Fix family check and EXP bug

[Emistry]

Pull Request Prelude

• I have followed proper Hercules code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

• failsafe function to not execute the query
• avoid EXP sharing bug

This adds a failsafe function to not execute the query during the family check AND avoid an exp sharing bug when the child_id is == 0 AND the returning value from the SQL is 0 also, this makes the check on char_child function returns a FALSE 1(positive)

Issues addressed:
rathena/rathena#3350

[HerculesWSAPI]

This change is