Function overload clash for custom types

## Description

When overriding an interface function with a custom type that has the same base type, the error `Function overload clash during conversion to external types for arguments` is emitted by the compiler. Emitting an error does make sense for type safety, but it could be useful to make it more apparent what the issue is.

## Environment

- Compiler version: latest
- Target EVM version (as per compiler settings): Paris
- Framework/IDE (e.g. Truffle or Remix): Foundry
- EVM execution environment / backend / blockchain client:
- Operating system: MacOS Sonoma

## Steps to Reproduce

```
type CustomType is uint256;

interface IPoc {
function isType(uint256 typeID) external view returns (bool);
}

contract Poc is IPoc {
function isType(CustomType typeID) external view returns (bool) {
return false;
}
}
```

Start by compiling the supplied Solidity snippet with the latest compiler and trace where the overload-clash diagnostic is produced. No source file or test is named; done means the diagnostic clearly identifies the interface/base-type conflict while preserving the type-safety error.

Written by the indexing model from the issue text.