Drop use of deprecated `method parameter of starlette FileResponse`

Removed in starlette 1.0, see https://github.com/Kludex/starlette/pull/3147

Fix the following mypy errors in package tests:

```
galaxy/webapps/base/api.py:94: error: Too many arguments for "__init__" of
"FileResponse"  [call-arg]
            super().__init__(
            ^~~~~~~~~~~~~~~~~
galaxy/webapps/base/api.py:95: error: Argument 8 to "__init__" of
"FileResponse" has incompatible type "str | None"; expected "str"  [arg-type]
    ..., media_type, background, filename, stat_result, method, content_dispo...
                                                        ^~~~~~
```

lib/galaxy/webapps/base/api.py

@@ -88,11 +88,17 @@ class GalaxyFileResponse(FileResponse):
         background: Optional["BackgroundTask"] = None,
         filename: Optional[str] = None,
         stat_result: Optional[os.stat_result] = None,
-        method: Optional[str] = None,
         content_disposition_type: str = "attachment",
     ) -> None:
         super().__init__(
-            path, status_code, headers, media_type, background, filename, stat_result, method, content_disposition_type
+            path=path,
+            status_code=status_code,
+            headers=headers,
+            media_type=media_type,
+            background=background,
+            filename=filename,
+            stat_result=stat_result,
+            content_disposition_type=content_disposition_type,
         )
         self.headers["accept-ranges"] = "bytes"
         self.xsendfile = self.nginx_x_accel_redirect_base or self.apache_xsendfile

lib/galaxy/webapps/galaxy/api/datasets.py

@@ -290,7 +290,7 @@ class FastAPIDatasets:
         assert isinstance(display_data, IOBase)
         file_name = getattr(display_data, "name", None)
         assert file_name
-        return GalaxyFileResponse(file_name, headers=headers, method=request.method)
+        return GalaxyFileResponse(file_name, headers=headers)
 
     @router.get(
         "/api/histories/{history_id}/contents/{history_content_id}/display",
@@ -374,7 +374,7 @@ class FastAPIDatasets:
         if isinstance(display_data, IOBase):
             file_name = getattr(display_data, "name", None)
             if file_name:
-                return GalaxyFileResponse(file_name, headers=headers, method=request.method)
+                return GalaxyFileResponse(file_name, headers=headers)
         elif isinstance(display_data, ZipstreamWrapper):
             return StreamingResponse(display_data.response(), headers=headers)
         elif isinstance(display_data, bytes):