web: ReactiveBase theme provider overwrites the outer theme provider

**Issue Type:**

Enhancement

**Platform:**

Web

**Description:**

When `ReactiveBase` is present as a child or deeper in the tree and wrapped by another emotion `ThemeProvider`, it will overwrite the `theme` keys of the outer `ThemeProvider`. A possible solution is to use a different key in reactivesearch itself:

```js

...


// got theme from ReactiveSearch instead

```

**Reactivesearch version:** x.y.z

v2.6.9