Headers in Table don't calculate the size correctly if using emoticons like "🧪"

For some reason with the following code :
```js
const baseColumns = [
["🧪aaaa", ""],
["A", "B"]
];

const config = {
spanningCells: [{ col: 0, row: 0, colSpan: 2 }]
};

console.log(table(baseColumns, config));
```

We get the following error from table :
subjectWidth: 6 , containerwidth:5
node_modules/table/dist/src/alignString.js
```
if (subjectWidth > containerWidth) {
throw new Error('Subject parameter value width cannot be greater than the container width.');
}
```

This does not repro if I remove the emoticon

```js
const baseColumns = [
["aaaaaaaaaaaaaaaaaaaaaa", ""],
["A", "B"]
];

const config = {
spanningCells: [{ col: 0, row: 0, colSpan: 2 }]
};

console.log(table(baseColumns, config));

```
output.

```
╔═══════╗
║ aaaaa ║
║ aaaaa ║
║ aaaaa ║
║ aaaaa ║
║ aa ║
╟───┬───╢
║ A │ B ║
╚═══╧═══╝
```

Note this also repros if I use colSpan instead of header.