fix: clear 10 more services from pyright ignore list

A second pass over the low-error-count files in the ignore list. Drops
10 files (77 → 67) and full-pyright errors from 580 → 555. Default
pyright stays clean.

Three coherent shapes plus a handful of one-offs:

`Language | str | None` → `Language | None` at STT frame boundaries.
`assert_given(self._settings.language)` returns `Language | str | None`
(strips `_NotGiven`, keeps the rest), but `TranscriptionFrame.language`
expects `Language | None`. In practice both `_settings.language` and
SDK-supplied codes resolve to a `Language` enum value, but technically
they could be raw strings — and `Language` is a StrEnum, so downstream
consumers (which mostly compare/serialize as strings) handle either.
Used `cast("Language | None", ...)` at each call site rather than a
runtime-validating helper, so an unrecognised code (e.g. one we
haven't added to the enum yet) still flows through unchanged. Cleared
azure/stt.py, aws/stt.py, gradium/stt.py; mistral/stt.py keeps the
cast at the SDK boundary (storing under `_detected_language: Language
| None`) but stays in the ignore list because of two unrelated
Optional-access errors.

aiobotocore `async with` stub gap. `aioboto3.Session().client(...)`
is an async context manager at runtime but its stubs don't advertise
`__aenter__`/`__aexit__` to pyright. Scoped
`# pyright: ignore[reportGeneralTypeIssues]` on the two affected
sites: aws/agent_core.py and aws/tts.py. aws/tts.py also had a latent
bug on the no-`AudioStream` path: the original code set
`audio_data = None` and then crashed in `resample(...)` and
`len(audio_data)` below; replaced with an early `return` after
logging — matches the convention elsewhere (OpenAI TTS, etc.) of not
recording usage metrics on the error path.

heygen `event_id: str | None` → `str` at transport→client boundary.
Three call sites in transports/heygen/transport.py passed `self._event_id`
(`str | None`) into client methods that take `str`. Added a guard at
each: `agent_speak_end` and `interrupt` only fire when `_event_id` is
set; `write_audio_frame` warn-and-drops when there's no active bot
event rather than sending a malformed message.

`OpenAIResponsesLLMInvocationParams` TypedDict.
`get_llm_invocation_params` always sets both `input` and `tools` in
the same dict literal, but the TypedDict was `total=False` so direct
subscript access (`invocation_params["input"]`) tripped
`reportTypedDictNotRequiredAccess` in services/openai/responses/llm.py.
Marked both keys `Required[...]`; `instructions` stays non-required
since it's only added when a system instruction is present.

Latent bug in heygen/api_interactive_avatar.py: the code accessed
`request_data.voice.voiceId` and `request_data.voice.elevenlabsSettings`,
but those names are Pydantic *aliases*; the actual attribute names
(used for attribute access) are `voice_id` and `elevenlabs_settings`.
Switched to the field names — those camelCase accesses would have
raised AttributeError at runtime if `voice` was set.

Other small fixes:

- assemblyai/stt.py: the deprecated `connection_params=` init path
  was reading `formatted_finals` and `word_finalization_max_wait_time`
  off `AssemblyAIConnectionParams`, but those fields were never on
  the deprecated input model — they were added to Settings later.
  Removed the reads (with a comment noting they're only available
  via the canonical `settings=...` API); the deprecated input model
  is unchanged.
- rtvi/processor.py: two `about: Mapping[str, Any] = None` parameter
  signatures — declared `Mapping`, defaulted to `None`, and both
  function bodies already handled the None case. Widened to
  `Mapping[str, Any] | None = None`.
- aws/stt.py: `subprotocols=["mqtt"]` failed against websockets'
  `Sequence[Subprotocol] | None` (Subprotocol is a NewType wrapper).
  Wrapped: `subprotocols=[Subprotocol("mqtt")]`.

Files dropped from the ignore list (77 → 67):
processors/frameworks/rtvi/processor.py, services/assemblyai/stt.py,
services/aws/agent_core.py, services/aws/stt.py, services/aws/tts.py,
services/azure/stt.py, services/gradium/stt.py,
services/heygen/api_interactive_avatar.py,
services/openai/responses/llm.py, transports/heygen/transport.py.

src/pipecat/processors/frameworks/rtvi/processor.py

@@ -102,7 +102,7 @@ class RTVIProcessor(FrameProcessor):
         self._client_ready = True
         await self._call_event_handler("on_client_ready")
 
-    async def set_bot_ready(self, about: Mapping[str, Any] = None):
+    async def set_bot_ready(self, about: Mapping[str, Any] | None = None):
         """Mark the bot as ready and send the bot-ready message.
 
         Args:
@@ -404,7 +404,7 @@ class RTVIProcessor(FrameProcessor):
         )
         await self.push_frame(frame)
 
-    async def _send_bot_ready(self, about: Mapping[str, Any] = None):
+    async def _send_bot_ready(self, about: Mapping[str, Any] | None = None):
         """Send the bot-ready message to the client.
 
         Args: