Check if dataset has any data at all before doing datatype-specific c…

…hecks

Fixes
https://sentry.galaxyproject.org/share/issue/64d122b1f85748da9009b13ca82917c9/:
```
error: unpack requires a buffer of 4 bytes
  File "starlette/applications.py", line 123, in __call__
    await self.middleware_stack(scope, receive, send)
  File "starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "starlette_context/middleware/raw_middleware.py", line 92, in __call__
    await self.app(scope, receive, send_wrapper)
  File "starlette/middleware/base.py", line 189, in __call__
    with collapse_excgroups():
  File "contextlib.py", line 155, in __exit__
    self.gen.throw(typ, value, traceback)
  File "starlette/_utils.py", line 93, in collapse_excgroups
    raise exc
  File "starlette/middleware/base.py", line 191, in __call__
    response = await self.dispatch_func(request, call_next)
  File "galaxy/webapps/galaxy/fast_app.py", line 109, in add_x_frame_options
    response = await call_next(request)
  File "starlette/middleware/base.py", line 165, in call_next
    raise app_exc
  File "starlette/middleware/base.py", line 151, in coro
    await self.app(scope, receive_or_disconnect, send_no_error)
  File "starlette/middleware/exceptions.py", line 65, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "starlette/routing.py", line 756, in __call__
    await self.middleware_stack(scope, receive, send)
  File "starlette/routing.py", line 776, in app
    await route.handle(scope, receive, send)
  File "starlette/routing.py", line 297, in handle
    await self.app(scope, receive, send)
  File "starlette/routing.py", line 77, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "starlette/routing.py", line 72, in app
    response = await func(request)
  File "fastapi/routing.py", line 278, in app
    raw_response = await run_endpoint_function(
  File "fastapi/routing.py", line 193, in run_endpoint_function
    return await run_in_threadpool(dependant.call, **values)
  File "starlette/concurrency.py", line 42, in run_in_threadpool
    return await anyio.to_thread.run_sync(func, *args)
  File "anyio/to_thread.py", line 56, in run_sync
    return await get_async_backend().run_sync_in_worker_thread(
  File "anyio/_backends/_asyncio.py", line 2144, in run_sync_in_worker_thread
    return await future
  File "anyio/_backends/_asyncio.py", line 851, in run
    result = context.run(func, *args)
  File "galaxy/webapps/galaxy/api/datasets.py", line 446, in show
    return self.service.show(trans, dataset_id, hda_ldda, serialization_params, data_type, **extra_params)
  File "galaxy/webapps/galaxy/services/datasets.py", line 384, in show
    rval = self._converted_datasets_state(
  File "galaxy/webapps/galaxy/services/datasets.py", line 848, in _converted_datasets_state
    if not data_provider.has_data(chrom):
  File "galaxy/visualization/data_providers/genome.py", line 1185, in has_data
    f, bbi = self._get_dataset()
  File "galaxy/visualization/data_providers/genome.py", line 1319, in _get_dataset
    return f, BigWigFile(file=f)
  File "lib/bx/bbi/bigwig_file.pyx", line 174, in bx.bbi.bigwig_file.BigWigFile.__init__
  File "lib/bx/bbi/bbi_file.pyx", line 129, in bx.bbi.bbi_file.BBIFile.__init__
  File "lib/bx/bbi/bbi_file.pyx", line 139, in bx.bbi.bbi_file.BBIFile.open
  File "bx/misc/binary_file.py", line 42, in __init__
    if struct.unpack(">I", bytes)[0] == magic:
```

lib/galaxy/webapps/galaxy/services/datasets.py

@@ -845,7 +845,7 @@ def _converted_datasets_state(
             data_provider = self.data_provider_registry.get_data_provider(
                 trans, original_dataset=dataset, source="index"
             )
-            if not data_provider.has_data(chrom):
+            if not dataset.has_data() or not data_provider.has_data(chrom):
                 return dataset.conversion_messages.NO_DATA
 
         # Have data if we get here