Improve seed phrase in memory

[Dmitry-Borodin]

Combine flows that are requiring seed phrase in single component / function in order to
1 Make sure seed will not live longer than the flow it's used in accidentally
2 Call System.gc() at the end to decrease of possibility for it to be found in memory.

[Dmitry-Borodin]

leftover - screens where seed is used - check if we need to call gc() onDispose, if content of screen is released by compose internals by that time.
Maybe check other usages one more time.