Handle Null Org Domain in SimpleFIN for bank_id (#2836)

* Update main.ts - Handle Null Org Domain in SimpleFIN

SimpleFIN (currently) uses the org domain as the bank ID. According to SimpleFIN docs, this can possibly be a null value, as can the org name. However, at least one of the two must be present.

In Actual, org name is set to "Unknown" if it comes in as null, but the bank_id (previously just set to the org domain) was not, resulting in a null bank_id value at times.

* Create 2836.md

* Fix release notes format.

* Small change to release note.

* Change to use new org Id as fallback for bank_id

* Add orgId property, for new org id from SimpleFIN