fix: remove memoryleaks in Coinbase and Explore

[HashEngineering]

Issue being fixed or feature implemented

Remove memory leaks related never unsubscribing from:

1. setOnApplyWindowInsetsListener
2. onBackPressedDispatcher.addCallback

Related PR's and Dependencies

Screenshots / Videos

How Has This Been Tested?

• [ ] QA (Mobile Team)

Checklist:

• [ ] I have performed a self-review of my own code and added comments where necessary
• [ ] I have added or updated relevant unit/integration/functional/e2e tests

[HashEngineering]

I will see about removing the EnterAmount* related memory leaks soon.