Stats: apply API changes to prevent reset

[leandroalonso]

We had a few instances of users' complaining that their Stats reset or reduced. This PR applies the latest changes deployed on Staging ensuring:

1. That the backend never "reduces" (or reset) any Stat;
2. That we pull back the stats in case we need

To test

1. First, change the Build Configuration to Staging and run the app
2. Login to a staging account
3. Ensure this account has some Stats. If it doesn't, manipulate these lines and trigger a refresh (just add numbers there)
4. Then, remove all the updateQueue.sync block from the StatsManager init method. This will simulate having negative stats
5. Go to Stats
6. ✅ Reduced Stats should appear but it should update to the correct one
7. Re-run the app
8. Trigger a refresh from Profile
9. Go to Stats
10. ✅ Stats should be correct

Checklist

• I have considered if this change warrants user-facing release notes and have added them to CHANGELOG.md if necessary.
• I have considered adding unit tests for my changes.
• I have updated (or requested that someone edit) the spreadsheet to reflect any new or changed analytics.

[leandroalonso]

I'm debating whether this should be 100 or something bigger or smaller.

Maybe if the local stat is just smaller than remote we should update?

[SergioEstevao]

Nit: Do you want to save only if the difference is positive right? No need to use abs ?

[SergioEstevao]

Followed the test instructions and the stats recovered to the correct values.
Just left a small nit that you may want to consider, but feel free to ignore if does not make sense for the scenario.