fix: missing setState for isInitialSetupComplete (#135)

## Description
- Follow-up from PR #134
- Adds in the missing setState for updating isInitialSetupComplete. I
must of deleted it by accident when I was removing all my console logs 😞

Co-authored-by: Stephen Gill <stephen.gill@adevinta.com>

src/components/AdvertisingProvider.js

@@ -20,6 +20,8 @@ export default class AdvertisingProvider extends Component {
   async componentDidMount() {
     if (this.advertising.isConfigReady() && this.props.active) {
       await this.advertising.setup();
+      // eslint-disable-next-line react/no-did-mount-set-state
+      this.setState({ isInitialSetupComplete: true });
     }
   }