“In cases where the execution of a conveyance is disputed, the onus is on the plaintiff to prove the legitimacy of the document’s execution. This principle is underscored when the defendant presents a consistent denial of their signature on the disputed document, as was the case with Chief Tijani Babalola. The absence of corroborative evidence from an attesting witness or a handwriting expert can significantly undermine the plaintiff’s case, leaving the court to rely on the evidence presented by the defense.”