Modernize Python typing across the codebase

Automated via ruff UP006, UP007, UP035, UP045 rules (target: py311):

- Replace `typing.List`, `Dict`, `Tuple`, `Set`, `FrozenSet`, `Type`
  with their built-in equivalents (`list`, `dict`, `tuple`, etc.)
- Replace `typing.Optional[X]` with `X | None`
- Replace `typing.Union[X, Y]` with `X | Y`
- Move `Mapping`, `Sequence`, `Callable`, `Awaitable`,
  `MutableMapping`, `MutableSequence`, `Iterator`, `AsyncIterator`,
  `AsyncGenerator` imports from `typing` to `collections.abc`
- Remove now-unused `typing` imports
- Add `from __future__ import annotations` to 5 files that use
  forward-reference strings in `X | "Y"` annotations

examples/persistent-context/persistent-context-aws-nova-sonic.py

@@ -105,7 +105,7 @@ async def load_conversation(params: FunctionCallParams):
         filename = params.arguments["filename"]
         logger.debug(f"loading conversation from {filename}")
         try:
-            with open(filename, "r") as file:
+            with open(filename) as file:
                 messages = json.load(file)
                 # HACK: if using the older Nova Sonic (pre-2) model, you need a special way of
                 # triggering the first assistant response. The call to trigger_assistant_response(),