SDK discards non-string Custom Attributes values

[markwpearce]

When the task is building the message to be sent, all non-string custom attributes are discarded. The mpPublicModels.Message() function will specifically ignore any attribute value that does not pass an mputils.isString() check:

See code here: https://github.com/mParticle/mparticle-roku-sdk/blob/master/mParticleCore.brs#L1379

                    mputils = mparticle()._internal.utils
                    attributeKeys = attributes.Keys()
                    validAttributes = {}
                    for each attributeKey in attributeKeys
                        if (mputils.isString(attributes[attributeKey])) then
                            validAttributes[attributeKey] = attributes[attributeKey]
                        end if
                    end for
                    attributes = validAttributes