Fix Broken Account Re-linking Feature (#469)

* Update SimpleFIN relinking flow and enhance duplicate account handling

- Updated logic to allow relinking of SimpleFIN accounts while preserving legacy mappings.
- Introduced clean-up logic to hide orphaned duplicate accounts after relinking.
- Enhanced UI to display current mappings for linked accounts.
- Improved test coverage for relinking scenarios and SimpleFIN account visibility.

* Localize SimpleFIN account selection messages and remove hardcoded text

- Added translations for user-facing messages in `select_existing_account` flow (`pt-BR` and `en` locales).
- Replaced hardcoded strings in the view with localized keys.

* Localize Enable Banking and SimpleFIN account linking messages; add support for investment accounts.

- Added translations for Enable Banking and SimpleFIN account linking flows.
- Updated views and controllers to replace hardcoded strings with localized keys.
- Introduced support for investment accounts in `Provider::LunchflowAdapter`.
- Enhanced relinking logic for SimpleFIN accounts and improved test coverage for related scenarios.

---------

Co-authored-by: Josh Waldrep <joshua.waldrep5+github@gmail.com>

app/models/provider/lunchflow_adapter.rb

@@ -7,7 +7,7 @@ class Provider::LunchflowAdapter < Provider::Base
 
   # Define which account types this provider supports
   def self.supported_account_types
-    %w[Depository CreditCard Loan]
+    %w[Depository CreditCard Loan Investment]
   end
 
   # Returns connection configurations for this provider