[Bug]: all statements with `.` are reported as external calls

### Describe the issue:

I ran `slither . --print function-summary` to view external calls for functions. The resulting "External Calls" column treats any statement with a `.` as an external call. This includes solidity built-ins like `abi.encode`, library accesses like `Address.sendValue`, and struct field accesses.

### Code example to reproduce the issue:

```bash
git clone https://github.com/scopelift/pooltogether-governor-upgrade/
cd pooltogether-governor-upgrade
forge install
slither . --print function-summary
```

### Version:

0.9.6

### Relevant log output:

_No response_