Update examples, wherever possible, to use LLMContext and associated machinery instead of OpenAILLMContext and associated machinery.

With all these examples updated, we no longer need dedicated examples illustrating `LLMContext`, so they're removed.

Here’s where we *don’t* yet use `LLMContext` and associated machinery:
- Realtime services: OpenAI Realtime, Gemini Live, and AWS Nova Sonic (support coming soon)
- `GoogleLLMOpenAIBetaService` (it’s deprecated, so we didn’t bother adding support)
- `LLMLogObserver` (support coming soon)
- `GatedOpenAILLMContextAggregator` (support coming soon)
- `LangchainProcessor` (support coming soon)
- `Mem0MemoryService` (support coming soon)
- Examples that use LLM-specific tools definitions as opposed to `ToolsSchema` (these will be updated soon)
- Examples that rely `GoogleLLMContext.upgrade_to_google` (TBD what to do with these)

Examples that use `LLMLogObserver`:
- 30-

Examples that use `GatedOpenAILLMContextAggregator`:
- 22-

Examples that use `LangchainProcessor`:
- 07b-

Examples that use `Mem0MemoryService`:
- 37-

Examples that need updating to use `ToolsSchema`:
- 15-
- 15a-
- 20a-
- 20c-
- 20d-
- 22b-
- 22c-
- 33-
- 36-

Examples that use `GoogleLLMContext.upgrade_to_google`:
- 22d-
- 25-

scripts/evals/run-release-evals.py

@@ -135,25 +135,6 @@ TESTS_14 = [
     ("14r-function-calling-aws.py", PROMPT_WEATHER, EVAL_WEATHER, BOT_SPEAKS_FIRST),
     ("14v-function-calling-openai.py", PROMPT_WEATHER, EVAL_WEATHER, BOT_SPEAKS_FIRST),
     ("14w-function-calling-mistral.py", PROMPT_WEATHER, EVAL_WEATHER, BOT_SPEAKS_FIRST),
-    ("14x-function-calling-universal-context.py", PROMPT_WEATHER, EVAL_WEATHER, BOT_SPEAKS_FIRST),
-    (
-        "14y-function-calling-google-universal-context.py",
-        PROMPT_WEATHER,
-        EVAL_WEATHER,
-        BOT_SPEAKS_FIRST,
-    ),
-    (
-        "14z-function-calling-anthropic-universal-context.py",
-        PROMPT_WEATHER,
-        EVAL_WEATHER,
-        BOT_SPEAKS_FIRST,
-    ),
-    (
-        "14aa-function-calling-aws-universal-context.py",
-        PROMPT_WEATHER,
-        EVAL_WEATHER,
-        BOT_SPEAKS_FIRST,
-    ),
     # Currently not working.
     # ("14c-function-calling-together.py", PROMPT_WEATHER, EVAL_WEATHER, BOT_SPEAKS_FIRST),
     # ("14l-function-calling-deepseek.py", PROMPT_WEATHER, EVAL_WEATHER, BOT_SPEAKS_FIRST),