Fix Android import first wallet navigation stack

[walmat]

Fixes APP-2259

What changed (plus any additional context for devs)

1. Seed Phrase Handling

• Added trimming of seed phrases during import to prevent whitespace issues:

const handleSetSeedPhrase = useCallback(
  (text: string) => {
    if (isImporting) return null;
    return setSeedPhrase(text.trim());
  },
  [isImporting]
);

2. Wallet Loading State Management

• Added new wallet loading state tracking during import process:

walletLoadingStore.setState({
  loadingState: WalletLoadingStates.IMPORTING_WALLET,
});

• Properly clearing loading state after import completion:

walletLoadingStore.setState({
  loadingState: null,
});

3. Navigation Flow Improvements

• Simplified navigation logic after wallet import
• Removed redundant navigation code paths
• Unified navigation handling through Navigation.handleAction:

Navigation.handleAction(
  Routes.SWIPE_LAYOUT,
  { screen: Routes.WALLET_SCREEN },
  previousWalletCount === 0
);

4. Code Cleanup

• Removed unused imports:
  • Removed isValidBluetoothDeviceId
  • Removed WalletBackupStepTypes
  • Removed IS_TEST
• Removed debug console logs from Portal component
• Improved code organization and readability

This PR focuses on improving the wallet import experience by handling edge cases better, providing clearer loading states, and simplifying the navigation flow after import completion.

Screen recordings / screenshots

https://rainbowhaus.slack.com/archives/C0468CDBE75/p1736530454941719

What to test

importing, watching, restoring from backup, etc. etc.

[linear]

APP-2259 Android navigation from initial wallet import results in tabs not being scrollable

[walmat]

this removes any extraneous newlines when pasting. Got tired of seeing that.

[brunobar79]

Launch in simulator or device for b20e671

[brunobar79]

Launch in simulator or device for a48f6cc

[derHowie]

Could be wrong but I think the most recent rebase removed 2 imports that file still wants

[derHowie]

Will approve after lint fix 🫡

[brunobar79]

Launch in simulator or device for 0cf2342