`DL2EventLoader.make_event_weights`: events outside fov_offset_bins keep default weight of 1

[Hckjs]

Thanks to @maxnoe for discusion: this issue arised during #2789, when using diffuse gammas to calculate/optimize point source sensitivity in fov_offset bins. DL2EventLoader.make_event_weights only updates the weights inside the offset-bin masks. Events outside the min/max fov_offset_bins range keep their default weight of 1, which can unintentionally include out-of-range events in downstream cut optimization. In contrast, the Sensitivity2DMaker used in the IRFTool explicitly masks/cuts signal events within the loop over fov_offset_bins, so out-of-range events are not included there.

Its already fixed in #2927 by setting the weights default to 0 and then updating per fov_offset bin

[maxnoe]

Its already fixed in #2927 by setting the weights default to 0 and then updating per fov_offset bin

#2927 just adds a new class for event weighting, for it to fix the issue it should actually be used in the cut optimization / sensitvity computation.