fix(transfer): respect node capacity limit in custom setup

[pwltr]

Description

• Include existing channels when calculating client and lsp balances for the custom setup.
• ChannelList buttons navigate to custom setup (as per design)

Linked Issues/Tasks

Closes #1563

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 (improving code without creating new functionality)

Tests

• Detox test
• Unit test
• No test

Screenshot / Video

Simulator.Screen.Recording.-.iPhone.15.-.2024-06-04.at.17.58.54.mp4

QA Notes

Custom Setup should not let you open a channel that puts you over the LSP node capacity limit (preventing the channel from being opened)