RUBY-3824 Restore conditional skip logic in transactions spec runner

A rubocop autocorrect in commit 8db6431 flattened the original
guarded skips into bare `skip` calls inside a single before(:all)
block, so every transactions and transactions_api example was
unconditionally pending with "Requirements not satisfied" (or
"No reason given") regardless of topology or other requirements.

Restore the original behavior: skip on `test.skip_reason` only when
one is set, skip on unmet requirements only when `req.satisfied?` is
false. Receive `req` from the block instead of `_req`.

Author: comandeo-mongo

spec/runners/transactions.rb

@@ -25,7 +25,7 @@ def define_transactions_spec_tests(test_paths, expectations_bson_types: true)
     spec = Mongo::Transactions::Spec.new(file)
 
     context(spec.description) do
-      define_spec_tests_with_requirements(spec) do |_req|
+      define_spec_tests_with_requirements(spec) do |req|
         spec.tests(expectations_bson_types: expectations_bson_types).each do |test|
           context(test.description) do
             before(:all) do
@@ -38,9 +38,8 @@ def define_transactions_spec_tests(test_paths, expectations_bson_types: true)
                   skip 'Test does not specify multiple mongoses'
                 end
               end
-              skip test.skip_reason
-
-              skip 'Requirements not satisfied'
+              skip test.skip_reason if test.skip_reason
+              skip 'Requirements not satisfied' unless req.satisfied?
 
               test.setup_test
             end