`electronicFormatIBAN` allows leading and trailing dashes

**Describe the bug**

`electronicFormatIBAN` allows leading and trailing dashes, thus letting invalid strings pass the validation.

**To Reproduce**
```js
const formatted = ibantools.electronicFormatIBAN('-- DE02 1203 0000 0000 2020 51 --')

// expected: null
// actual: DE02120300000000202051
```

**Environment:**

`ibantools: 4.5.1`
`node: 22.21.1`