Add missing GEN_AI_RESPONSE_ID_KEY constant to fix test import error

Co-authored-by: nikhilNava <211831449+nikhilNava@users.noreply.github.com>

Author: Copilot

libraries/microsoft-agents-a365-observability-core/microsoft_agents_a365/observability/core/constants.py

@@ -34,6 +34,7 @@
 GEN_AI_REQUEST_TOP_P_KEY = "gen_ai.request.top_p"
 GEN_AI_RESPONSE_FINISH_REASONS_KEY = "gen_ai.response.finish_reasons"
 GEN_AI_RESPONSE_MODEL_KEY = "gen_ai.response.model"
+GEN_AI_RESPONSE_ID_KEY = "gen_ai.response.id"
 GEN_AI_AGENT_ID_KEY = "gen_ai.agent.id"
 GEN_AI_AGENT_NAME_KEY = "gen_ai.agent.name"
 GEN_AI_AGENT_DESCRIPTION_KEY = "gen_ai.agent.description"