fix app hang up pt 2

[mike-dydx]

Description / Intuition

• app hangs 50% of the time after start
• issue is still with firebase not calling the call back in fetchAndActivate so must wait for a new version
• moved completion out of fetchAndActivate callback. As a result remote flags maybe never load properly so a/b testing will be broken until firebase fixes. No remote flags are active though since they are managed via env json instead.
• upgrades to newest firebase pods

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactoring or Technical Debt
• Documentation update
• Other (please describe: )