Remove exception from decoding issued currencies which evaluate to 'XRP' (#1920)

* Remove throw and revise tests

* Update chai dependency

* Disabling linter error about extraneous import

* Fix typo in test description

* Revert unnecessary test changes

* Remove unnecessary comments

* Revert chai change

* Add HISTORY.md

* Revert chai change in package-lock as well

* Fix typo

* Check the result of the decoding

* Update tests with correct expected behavior.

* Fix tests and update currency.js

* Update currency.ts

packages/ripple-binary-codec/src/types/currency.ts

@@ -29,9 +29,7 @@ function isIsoCode(iso: string): boolean {
 function isoCodeFromHex(code: Buffer): string | null {
   const iso = code.toString()
   if (iso === 'XRP') {
-    throw new Error(
-      'Disallowed currency code: to indicate the currency XRP you must use 20 bytes of 0s',
-    )
+    return null
   }
   if (isIsoCode(iso)) {
     return iso