Add default slippage to remote config

[brunobar79]

Fixes RNBW-####
Figma link (if any):

What changed (plus any additional context for devs)

Added default slippage to remote config

Screen recordings / screenshots

Jumped on a call with @estebanmino to verify this works properly

What to test

You can change the value in the remote config, restart the app and it should be reflected in the slippage settings

Final checklist

• Assigned individual reviewers?
• Added labels? (team1/team2, critical path, release, dev QA)
• Did you test both iOS and Android?
• If your changes are visual, did you check both the light and dark themes?
• Added e2e tests? If not, please specify why
• If you added new critical path files, did you update the CODEOWNERS file?
• If no dev QA label, did you add the PR to the QA Queue?