Fix test bad connection test

[aidanharan]

Fixes:

https://github.com/rails-sqlserver/activerecord-sqlserver-adapter/actions/runs/9033092031/job/24822623240

AdapterTestSQLServer#test_0010_test bad connection [/activerecord-sqlserver-adapter/test/cases/adapter_test_sqlserver.rb:102]:
[ActiveRecord::NoDatabaseError] exception expected, not
Class: <NoMethodError>
Message: <"undefined method `sqlserver_connection' for class ActiveRecord::Base">
---Backtrace---
/usr/local/bundle/bundler/gems/rails-2744b74216e5/activerecord/lib/active_record/dynamic_matchers.rb:22:in `method_missing'
/activerecord-sqlserver-adapter/test/cases/adapter_test_sqlserver.rb:106:in `block (2 levels) in <class:AdapterTestSQLServer>'