[Bug]: Impossible to generate IR:  'list' object has no attribute 'type'

### Describe the issue:

A bit of a rare case, but...

### Code example to reproduce the issue:

```solidity
library Constants {
    uint8 constant value = [[1, 2], [3, 4]][0][0];
}
```

### Version:

0.9.1

### Relevant log output:

```shell
Impossible to generate IR for ConstantExpressions.slitherConstructorConstantVariables:
 'list' object has no attribute 'type'
```
