LP Token estimation in fiat : Why an exception if prices are = 0 ?

In `DexTokensProviders.estimateTokenInFiat` why have we an exception if prices are = 0
Normally, if tokens from LP have no price, LP Price = 0

```
if (fiatValueToken1 == 0 && fiatValueToken2 == 0) {
throw Exception();
}
```

Start at the DexTokensProviders.estimateTokenInFiat entry point and inspect the branch that throws when both fiatValueToken1 and fiatValueToken2 are zero. Confirm how LP tokens with no prices are represented elsewhere, then verify that the zero-price case follows the intended behavior without raising an exception.

Written by the indexing model from the issue text.