Timestamp does not render dates over a year ago

### Issue:
The `` component does not function with dates that are greater than 12 months old.

#### Example:
```javascript
let birthday = new Date('11:34 AM 04/Apr/1979');

```

#### Result:
> undefined ago

#### Expected result:
> 39 years ago

#### Area of code concerned:
https://github.com/Autodesk/hig/blob/8b9cd2b29d8f2e7b922e4a0e88c79daec74d9701/packages/vanilla/src/basics/timestamp/timestamp.js#L12

Start in packages/vanilla/src/basics/timestamp/timestamp.js at the linked line and reproduce the example with a date more than 12 months old. Trace how the component selects its elapsed-time wording, then verify that the example renders “39 years ago” rather than “undefined ago”.

Written by the indexing model from the issue text.