Update dispute guide for portal

[andrewnossiter]

We need to update the text for how to handle disputes in the API Docs section of our website. That text can be found here: https://docs.balancedpayments.com/1.1/guides/disputes/

The actual file is https://github.com/balanced/balanced-docs/blob/master/overview/rev1/guides/disputes.rst

Currently, this reads:

"Unfortunately, not all disputes are as easily resolved. If you are unable to reach a customer, or they are not being cooperative, the next steps are to gather as much documentation as possible to demonstrate fulfillment of the transaction and send it to support@balancedpayments.com. Balanced will use the supplied documentation to fight the dispute on your behalf directly with the credit card provider."

The new text should read:

"Unfortunately, not all disputes are as easily resolved. If you are unable to reach a customer, or they are not being cooperative, the next steps are to gather as much documentation as possible to demonstrate fulfillment of the transaction and submit it directly within the dispute portal in your Balanced dashboard. Balanced will then use the supplied documentation to fight the dispute on your behalf directly with the credit card provider."