Validation not in line with Dashboard validation, and therefore missing potential issues

[stevieflow]

See issue raised via Dashboard IATI/IATI-Dashboard#845 (comment)

I understand the Dashboard has a different library to parse the XML for validation, which results in different / better validation reports

The Validator doesn't therefore report on some XML schema validation issues (as opposed to IATI Rulesets), such as non numeric values being used, when a decimal is expected

Solution: the Validator should update to use the same process as the Dashboard, to support users fully, and surface all possible validation issues clearly

@Bjwebb @simon-20 @robredpath @emmajclegg

[stevieflow]

aics-org (1).xml attached is the XML file that contains this example issue