ci(circleci): switch coverage reporting to Qlty orb (#12337)

spec/coverage_helper.rb

@@ -0,0 +1,8 @@
+require 'simplecov'
+require 'simplecov_json_formatter'
+
+# Configure SimpleCov to emit JSON for Qlty and HTML locally if needed
+SimpleCov.formatter = SimpleCov::Formatter::JSONFormatter
+SimpleCov.start 'rails' do
+  SimpleCov.coverage_dir 'coverage'
+end