skip/disable/remove fetch config conditionally

Hi,

What I want to do is pretty simple and I thought it would be supported but I can't find such an option so far.

I have an input text on which I'd like to provide autocomplete. But I don't want to trigger requests unless the text size is > 2.

I've tried the following:

```js
const ConnectedCompanyField = connect(({ value }) => {
if (value.length > 2) {
return {
fieldValuesFetch: {
comparison: value,
value: () => searchField(value, ProviderLabel),
},
};
}
})(CompanyField);
```

Even if the `fieldValuesFetch` is not returned when text is small, the former `fieldValuesFetch` remains injected into the component. It looks like a bug to me, but maybe it's intended?

I think it would be easier to provide an ability to "skip" / "ignore" a fetch conditionnally.

Apollo provides an API similar to this:

```js
const ConnectedCompanyField = connect(({ value }) => {
fieldValuesFetch: {
comparison: value,
value: () => searchField(value, ProviderLabel),
skip: value.length <= 2,
},
})(CompanyField);
```