chore: set storage not 'migrable'

[patogallaiovlabs]

Issue
When the users resets/change phone, all data is migrated to the new phone, when for security reasons it shouldn't. The private data should 'live' only on the scope of the current device.

Tech description
rWallet uses lib rn-secure-storage for saving data in the device, from their docs they have some ways to set how to save data.
To fix it lets change to:

• WHEN_UNLOCKED_THIS_DEVICE_ONLY: The data in the keychain item can be accessed only while the device is unlocked by the user. Items with this attribute do not migrate to a new device.

What do we store?

• Passcode
• Mnemonic phrase
• Private key
• User password

How to test it

• Install the app in a new device with apple account set.
• Create a new wallet with new seed.
• Create a new device.
• Import apple account.
• When opening the app, we shouldn't get any wallet already created.

[martinmedina]

Code changes look good, definitely a security improvement to what we had before.
I tested on a device the following cases

1. install rwallet local build, create a wallet, backup seed, delete app, reinstall app and no data was available on the new install.
2. install rwallet local build, create a wallet, backup seed, backup full device on icloud, wipe device, restore backup from icloud on the same device and data was available on the new install.
   This case worked as expected since the data is available if the backup is restored on the same device.

A test that could not be done is case 2 but restoring the backup on a new device. For that case, the data should not be available.

As mentioned before, code looks good and since there is no way to do the remaining test on the short term I'm approving this PR.