fixed:issue->#1968 Import from nYNAB fails with unknown error (#2191)

* Allow case insensitive ynab5 import for special 'starting balance' payee

* set upcoming release number to related github issue

* extract string comparison into separate function

and reuse when checking starting balance/s on ynab4 import

* make all category group checks case insensitive

when importing from ynab5 to make the check strategy consistent when importing from ynab5

* extract findById into sreusable function

to 'simplify' usage

* Add null check

Co-authored-by: Joel Jeremy Marquez <joeljeremy.marquez@gmail.com>

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Co-authored-by: Joel Jeremy Marquez <joeljeremy.marquez@gmail.com>