Enables rules_scala's unused dependency checker by setting the attribute unused_dependency_checker_mode = "error" and removes unused dependencies on da_scala_library targets. This avoids unnecessary dependencies which is better for parallel builds and caching.

Some targets had their deps attribute factored out to a compileDependencies variable or similar. This makes "unused dependency checker" warnings harder to fix, so they have been inlined.

da_scala_test has been handled in #3925.
da_scala_binary has been handled in #3937.

Pull Request Checklist

• Read and understand the contribution guidelines
• Include appropriate tests
• Set a descriptive title and thorough description
• Add a reference to the issue this PR will solve, if appropriate
• Include changelog additions in one or more commit message bodies between the CHANGELOG_BEGIN and CHANGELOG_END tags, if appropriate
• Normal production system change, include purpose of change in description

NOTE: CI is not automatically run on non-members pull-requests for security
reasons. The reviewer will have to comment with /AzurePipelines run to
trigger the build.