update: fix error message

Author: FarhanAnjum-opti

lib/optimizely/decision_service.rb

@@ -530,7 +530,7 @@ def get_decision_for_cmab_experiment(project_config, experiment, user_context, b
         )
         CmabDecisionResult.new(false, cmab_decision, decide_reasons)
       rescue StandardError => e
-        error_message = "Failed to fetch CMAB data for experiment #{experiment['key']}"
+        error_message = "Failed to fetch CMAB data for experiment #{experiment['key']}."
         decide_reasons.push(error_message)
         @logger&.log(Logger::ERROR, "#{error_message} #{e}")
         CmabDecisionResult.new(true, nil, decide_reasons)

spec/decision_service_spec.rb

@@ -1078,7 +1078,7 @@
         expect(variation_result.cmab_uuid).to be_nil
         expect(variation_result.error).to eq(true)
         expect(variation_result.reasons).to include(
-          'Failed to fetch CMAB data for experiment cmab_experiment'
+          'Failed to fetch CMAB data for experiment cmab_experiment.'
         )
 
         # Verify CMAB service was called but errored