Fix budget limit test, and a bug in the other currencies corrector.

tests/Unit/Console/Commands/Upgrade/BudgetLimitCurrencyTest.php

@@ -47,7 +47,10 @@ class BudgetLimitCurrencyTest extends TestCase
      */
     public function testHandle(): void
     {
+        BudgetLimit::whereNull('transaction_currency_id')->forceDelete();
+
         $this->artisan('firefly-iii:bl-currency')
+            ->expectsOutput('All budget limits are correct.')
              ->assertExitCode(0);
     }