Remove unsued BackgroundModel import from detect.ipynb
"from gammapy.estimators.utils import find_peaks\n",
"from gammapy.datasets import MapDataset\n",
"from gammapy.modeling.models import (\n",
- " BackgroundModel,\n",
" SkyModel,\n",
" PowerLawSpectralModel,\n",
" PointSpatialModel,\n",
