Enhance security information retrieval and handling (#1826)

* Enhance security information retrieval and handling

- Add support for operating MIC codes in security info fetching
- Update security uniqueness validation to handle unknown securities
- Improve security creation and update logic in Plaid investment sync
- Update combobox and view components to handle operating MIC codes
- Add unknown flag for securities with incomplete information

* Update schema.rb

* Refactor the need for mic codes

* Don't fetch prices unless a security has the necessary mic code

* Deduplication

* Lint

* Update Securities and Plaid Investment Sync

- Modify PlaidInvestmentSync to return plaid_security for USD cash
- Add non-null constraint to Securities ticker column
- Update Securities fixture to use exchange_operating_mic instead of exchange_mic

---------

Signed-off-by: Josh Pigford <josh@joshpigford.com>

app/models/plaid_investment_sync.rb

@@ -82,12 +82,15 @@ class PlaidInvestmentSync
       end
 
       return [ nil, nil ] if plaid_security.nil? || plaid_security.ticker_symbol.blank?
+      return [ nil, plaid_security ] if plaid_security.ticker_symbol == "CUR:USD" # internally, we do not consider cash a security and track it separately
 
+      operating_mic = plaid_security.market_identifier_code
+
+      # Find any matching security
       security = Security.find_or_create_by!(
         ticker: plaid_security.ticker_symbol,
-        exchange_mic: plaid_security.market_identifier_code || "XNAS",
-        country_code: "US"
-      ) unless plaid_security.ticker_symbol == "CUR:USD" # internally, we do not consider cash a security and track it separately
+        exchange_operating_mic: operating_mic
+      )
 
       [ security, plaid_security ]
     end