Improve connection handling during dev dump reload

[gregorbg]

Addresses recent staging import problems

CC @dunkOnIT

[dunkOnIT]

Efforts to use this PR fail here:

ActiveRecord::Base.connection.exec("SOURCE #{DbDumpHelper::DEVELOPER_EXPORT_SQL}")

Minor issue - .exec is not valid AR syntax. However, changing to .execute yields this error:

Mysql2::Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SOURCE wca-developer-database-dump.sql' at line 1 (Mysql2::Error)

Talking to ChatGPT suggests that we have to pipe that command via MySQL, not AR. I dipped my toes in by trying to change it to DatabaseDumper.mysql(), which got me past that line of code but nuked my db in the process - I wasn't using reload[1].

I'm now reloading my dev db, and will modify the dev dump with a local parameter[2] and use that + LIMIT 100 to generate a dev dump I can use to test the new load.

[1] I figured that if I just had a file that inserted a line, I shouldn't use reload - which would create an unpopulated temp db - and should instead just have it applied directly on the existing database. That logic was probably flawed :P
[2] similar to how I did for the results dump

[dunkOnIT]

@thewca-bot deploy staging

[dunkOnIT]

Worked locally using my latest push, deploying to staging now to try it out there