cleanup: remove dupe tests, update lock and docs

- Remove tests from `ripple-keypairs` that exclusively tested
`rippled-address-codec`. The tests in `codec.test.ts` and
`xrp-codec.test.ts` are all present and accounted for in
`packages/ripple-address-codec/test/xrp-codec.test.ts`.
- Update `package-lock.json` after the rebase with main
- Remove references to `decimal.js` in the documentation

This will clean up the diff for #2273

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

@@ -17,7 +17,7 @@ const MIN_XRP = new BigNumber('1e-6')
 const mask = BigInt(0x00000000ffffffff)
 
 /**
- * decimal.js configuration for Amount IOUs
+ * BigNumber configuration for Amount IOUs
  */
 BigNumber.config({
   EXPONENTIAL_AT: [
@@ -207,7 +207,7 @@ class Amount extends SerializedType {
   /**
    * Validate IOU.value amount
    *
-   * @param decimal Decimal.js object representing IOU.value
+   * @param decimal BigNumber object representing IOU.value
    * @returns void, but will throw if invalid amount
    */
   private static assertIouIsValid(decimal: BigNumber): void {