Python: Add metrics instrumentation

[TaoChenOSU]

Motivation and Context

We very recently added instrumentation to kernel functions: #8280. That PR added logs and traces for observing a kernel function. This PR adds metrics and modifies the telemetry sample app to show how to export metric instruments to Application Insights.

Description

1. Kernel function now produces metrics data for observability.
2. Add code to export metric instruments to the telemetry sample.
3. Add Google AI as a second service to the telemetry sample to show case nested spans.
4. Mics optimizations.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[eavanvalkenburg]

couple of notes, but looks good otherwise!

[markwallace-microsoft]

Python Test Coverage Report

File	Stmts	Miss	Cover	Missing
semantic_kernel
kernel.py	199	47	76%	150, 161, 165, 315–318, 425, 439–482
semantic_kernel/agents/group_chat
agent_chat.py	116	1	99%	91
agent_group_chat.py	67	2	97%	113, 135
broadcast_queue.py	72	1	99%	35
semantic_kernel/agents/open_ai
open_ai_assistant_base.py	361	3	99%	243, 321–322
semantic_kernel/connectors/ai/anthropic/services
anthropic_chat_completion.py	94	25	73%	171–181, 196–205, 222–236
semantic_kernel/connectors/ai/azure_ai_inference/services
azure_ai_inference_chat_completion.py	150	4	97%	174, 324–325, 441
semantic_kernel/connectors/ai/embeddings
embedding_generator_base.py	8	1	88%	50
semantic_kernel/connectors/ai/google
shared_utils.py	39	2	95%	97, 119
semantic_kernel/connectors/ai/google/google_ai/services
google_ai_chat_completion.py	150	4	97%	153, 265, 299–300
utils.py	63	3	95%	139, 157–162
semantic_kernel/connectors/ai/google/vertex_ai/services
utils.py	65	3	95%	141, 159–164
vertex_ai_chat_completion.py	150	4	97%	147, 258, 292–293
semantic_kernel/connectors/ai/hugging_face/services
hf_text_completion.py	54	3	94%	97, 105, 136
hf_text_embedding.py	32	5	84%	79–83
semantic_kernel/connectors/memory/azure_ai_search
azure_ai_search_collection.py	87	2	98%	150, 152
semantic_kernel/connectors/memory/redis
redis_collection.py	160	2	99%	146, 316
utils.py	45	11	76%	145–146, 164, 166, 173–188
semantic_kernel/connectors/openapi_plugin
openapi_manager.py	58	2	97%	110–111
openapi_parser.py	88	1	99%	127
openapi_runner.py	105	2	98%	181–182
semantic_kernel/connectors/openapi_plugin/models
rest_api_operation.py	129	1	99%	242
semantic_kernel/contents
function_call_content.py	97	1	99%	201
semantic_kernel/data
vector_store_record_collection.py	249	19	92%	410, 470–474, 482–486, 526–529, 536–539
vector_store_record_utils.py	26	2	92%	50, 52
semantic_kernel/functions
kernel_function_decorator.py	98	1	99%	102
kernel_function_from_method.py	96	1	99%	153
kernel_function_from_prompt.py	154	7	95%	165–166, 180, 201, 219, 239, 322
kernel_function_log_messages.py	43	12	72%	20, 26, 32, 40–46, 58, 64, 70
kernel_plugin.py	187	2	99%	472, 475
semantic_kernel/planners
plan.py	234	45	81%	54, 163–165, 197, 214–227, 264, 269, 277–278, 288–291, 308, 313, 329, 332–337, 355, 360, 363, 365, 372, 386–388, 393–397
semantic_kernel/planners/function_calling_stepwise_planner
function_calling_stepwise_planner.py	116	4	97%	145, 189–190, 198
semantic_kernel/planners/sequential_planner
sequential_planner.py	64	6	91%	71, 75, 109, 125, 134–135
sequential_planner_extensions.py	50	9	82%	31–32, 56, 110–124
sequential_planner_parser.py	77	12	84%	66–74, 93, 117–120
semantic_kernel/schema
kernel_json_schema_builder.py	119	5	96%	50, 84, 206, 210–211
semantic_kernel/template_engine/blocks
code_block.py	77	1	99%	119
named_arg_block.py	43	1	98%	98
semantic_kernel/utils/telemetry
decorators.py	113	4	96%	232, 240, 243, 252
user_agent.py	16	2	88%	18–19
TOTAL	10782	263	98%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
2370	1 💤	0 ❌	0 🔥	51.218s ⏱️