HTML Widgets; Number Box Control; Validation is now skipped if allowBlank: true and the Control is blank

The Number Box control has been updated to prevent validation from failing where the Control is allowed to be blank (i.e., allowBlank: true) and is blank.

Previously, this was incorrectly stopping Users from proceeding. For example, if a Number Box had a minimum value of 1 and a maximum value of 100, a cleared Number Box would fail validation due to this. Now, the validation would be skipped and allow the User to proceed.

Note: If a blank value is to be treated as invalid, then ideally the allowBlank property should be set as false which will fail the validation if a blank value has been entered.