fix return user segmentation

[brindy]

Task/Issue URL: https://app.asana.com/0/414709148257752/1208380046395184/f
Tech Design URL:
CC:

Description:
Fix usage segmentation for return users.

Steps to test this PR:

1. Reset the simulator xcrun simctl erase all

2. Add the following lines to the start of the load func of StatisticsLoader:

    statisticsStore.variant = "ru"
    statisticsStore.atb = "v446-1"
    statisticsStore.appRetentionAtb = "v447-1"
    statisticsStore.searchRetentionAtb = "v447-2"
   

3. Run the app and check for a pixel like this:

    Pixel fired m.retention.segments ["count_as_mau_n": "tttt", "new_set_atb": "v448-7", "count_as_wau": "true", "segments_today": "first_month,reactivated_wau,reinstaller", "activity_type": "app_use"]
   

4. Ensure that reinstaller and "activity_type": "app_use" are in the parameters as above

5. Get through onboarding and do a search

6. Check for a similar pixel ensuring that reinstaller and "activity_type": "search" are in the parameters

Definition of Done (Internal Only):

• Does this PR satisfy our Definition of Done?

[aataraxiaa]

Tested and LGTM @brindy