[Analytics] Add metrics for what storage type is being used in redux persist

### **Description**

- add a user property that tracks what storage solution users are using for redux persist

### **Technical Details**
- could add a log [here](https://github.com/MetaMask/metamask-mobile/blob/main/app/store/index.js#L24)
- issue is Analytics isn't initialized until [here](https://github.com/MetaMask/metamask-mobile/blob/main/app/components/Nav/App/index.js#L241) which is before after this call so in order to make this work we would need to find a way to log this metric after app initialization
- A reference PR can be found [here](https://github.com/MetaMask/metamask-mobile/pull/3875)

### **Acceptance Criteria**

- when a user closes and re opens the app, we should set a user property informing us of what storage solution they are using
- this property should show up in mixpanel

### **References**

- we initially tried to this this in [this PR](https://github.com/MetaMask/metamask-mobile/pull/4655) but opted to revert the changes

Read app/store/index.js around the referenced line and app/components/Nav/App/index.js around the analytics initialization point. Review pull requests 3875 and 4655 to understand the prior approach and why it was reverted. The work is done when reopening the app sets the storage solution as a user property and that property appears in Mixpanel.

Written by the indexing model from the issue text.