Detect projects before running multi_scan

[tejassharma96]

Checklist

• I've run bundle exec rake from the root directory to see all new and existing tests pass
• I've read the Contribution Guidelines
• I've updated the documentation if necessary.

Motivation and Context

Fixes #362

Description

Run detect_projects on the options before starting multi_scan

[tejassharma96]

@lyndsey-ferguson this does cause all the multi_scan_manager/runner tests to fail since it stops at each test and says "Couldn't automatically detect the project file, please provide a path:". Any ideas on a way to update those to support this?

[tejassharma96]

I updated each test in that folder with the path to the AtomicBoy workspace. This appears to be how they do it when testing scan in fastlane too: https://github.com/fastlane/fastlane/blob/master/scan/spec/runner_spec.rb

This fixed the test issues.

[tejassharma96]

Would love to get some eyes on this if possible

[lyndsey-ferguson]

Hello @tejassharma96 , I want to apologize that I have not responded to this PR. A family health issue is requiring me to narrow my focus on the essentials and I don't have the time I need to focus on the plugin more than a minute. If you can get some other contributors to this project to review this, I would consider merging it.