list(dependencies or []) -> dependencies or []

As minor a side effect, when concatenating lists of dependencies it now uses `list(a).extend(b)` instead of `a.copy().extend(b)`, as
dependencies are defined to be a `Sequence` instead of a list, and .extend is only supported with lists

fastapi/routing.py

@@ -287,7 +287,7 @@ def __init__(
     ) -> None:
         self.path = path
         self.endpoint = endpoint
-        self.dependencies = list(dependencies or [])
+        self.dependencies = dependencies or []
         self.name = get_name(endpoint) if name is None else name
         self.path_regex, self.path_format, self.param_convertors = compile_path(path)
         self.dependant = get_dependant(path=path, call=self.endpoint)
@@ -373,7 +373,7 @@ def __init__(
             self.secure_cloned_response_field = None
         self.status_code = status_code
         self.tags = tags or []
-        self.dependencies = list(dependencies or [])
+        self.dependencies = dependencies or []
         self.summary = summary
         self.description = description or inspect.cleandoc(self.endpoint.__doc__ or "")
         # if a "form feed" character (page break) is found in the description text,
@@ -471,7 +471,7 @@ def __init__(
             ), "A path prefix must not end with '/', as the routes will start with '/'"
         self.prefix = prefix
         self.tags: List[Union[str, Enum]] = tags or []
-        self.dependencies = list(dependencies or [])
+        self.dependencies = dependencies or []
         self.deprecated = deprecated
         self.include_in_schema = include_in_schema
         self.responses = responses or {}
@@ -520,7 +520,7 @@ def add_api_route(
         current_tags = self.tags.copy()
         if tags:
             current_tags.extend(tags)
-        current_dependencies = self.dependencies.copy()
+        current_dependencies = list(self.dependencies)
         if dependencies:
             current_dependencies.extend(dependencies)
         current_callbacks = self.callbacks.copy()
@@ -621,7 +621,7 @@ def add_api_websocket_route(
         dependencies: Optional[Sequence[params.Depends]] = None,
         name: Optional[str] = None,
     ) -> None:
-        current_dependencies = self.dependencies.copy()
+        current_dependencies = list(self.dependencies)
         if dependencies:
             current_dependencies.extend(dependencies)