AB#3250444 Fixing user agent header name

[singankit]

Description

Appending header values if clashing headers found between injected headers and original headers in request.

All Promptflow Contribution checklist:

• The pull request does not introduce [breaking changes].
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.
• Create an issue and link to the pull request to get dedicated review from promptflow team. Learn more: suggested workflow.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[github-actions]

promptflow-evals test result

 12 files  + 3   12 suites  +3   1h 35m 52s ⏱️ - 1h 23m 2s
 35 tests  - 19   33 ✅  - 18   2 💤  - 1  0 ❌ ±0 
420 runs   - 66  396 ✅  - 63  24 💤  - 3  0 ❌ ±0 

Results for commit 44ab29d. ± Comparison against base commit 5a3396f.

This pull request removes 19 tests.

tests.evals.e2etests.test_adv_simulator.TestAdvSimulator ‑ test_adv_conversation_sim_responds_with_responses
tests.evals.e2etests.test_adv_simulator.TestAdvSimulator ‑ test_adv_qa_sim_responds_with_one_response
tests.evals.e2etests.test_adv_simulator.TestAdvSimulator ‑ test_adv_rewrite_sim_responds_with_responses
tests.evals.e2etests.test_adv_simulator.TestAdvSimulator ‑ test_adv_sim_init_with_prod_url
tests.evals.e2etests.test_adv_simulator.TestAdvSimulator ‑ test_adv_summarization_jailbreak_sim_responds_with_responses
tests.evals.e2etests.test_adv_simulator.TestAdvSimulator ‑ test_adv_summarization_sim_responds_with_responses
tests.evals.e2etests.test_adv_simulator.TestAdvSimulator ‑ test_incorrect_scenario_raises_error
tests.evals.e2etests.test_builtin_evaluators.TestBuiltInEvaluators ‑ test_composite_evaluator_content_safety
tests.evals.e2etests.test_builtin_evaluators.TestBuiltInEvaluators ‑ test_composite_evaluator_content_safety_chat[False-False]
tests.evals.e2etests.test_builtin_evaluators.TestBuiltInEvaluators ‑ test_composite_evaluator_content_safety_chat[True-False]
…

♻️ This comment has been updated with latest results.

[github-actions]

promptflow-tracing test result

 12 files  ±  0  12 suites  ±0   3m 49s ⏱️ + 3m 33s
 20 tests  -  42   8 ✅  -  54   12 💤 + 12  0 ❌ ±0 
240 runs   - 504  96 ✅  - 648  144 💤 +144  0 ❌ ±0 

Results for commit 44ab29d. ± Comparison against base commit 5a3396f.

This pull request removes 62 and adds 20 tests. Note that renamed tests count towards both.

tests.unittests.test_context_utils ‑ test_thread_pool_executor_with_context
tests.unittests.test_context_utils ‑ test_thread_pool_executor_with_context_async
tests.unittests.test_iterator_proxy ‑ test_generator_proxy_iter
tests.unittests.test_iterator_proxy ‑ test_generator_proxy_next
tests.unittests.test_iterator_proxy ‑ test_generator_proxy_type
tests.unittests.test_iterator_proxy ‑ test_iterator_proxy_iter
tests.unittests.test_iterator_proxy ‑ test_iterator_proxy_next
tests.unittests.test_openai_injector ‑ test_aoai_call_inject
tests.unittests.test_openai_injector ‑ test_get_aoai_telemetry_headers
tests.unittests.test_openai_injector ‑ test_inject_and_recover_openai_api
…

tests.e2etests.test_tracing.TestTracing ‑ test_open_ai_stream_context_manager
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace[dummy_llm_tasks_async-inputs1-3]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace[dummy_llm_tasks_threadpool-inputs2-5]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace[greetings-inputs0-4]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace_with_embedding[openai_embedding_async-inputs0-2]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace_with_embedding[openai_embedding_async-inputs1-2]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace_with_llm[openai_chat-inputs0-2]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace_with_llm[openai_chat-inputs2-2]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace_with_llm[openai_chat_async-inputs4-2]
tests.e2etests.test_tracing.TestTracing ‑ test_otel_trace_with_llm[openai_chat_async-inputs6-2]
…

♻️ This comment has been updated with latest results.

[singankit]

Fixes AB#3250444