Fix fake errors in DL2 to DL3 & Index creation step

[SeiyaNozaki]

Fix #1225 with some code refactoring. I updated codes adding case handling for IRF interpolation and index creation (point-like IRF: effective area and energy dispersion. full-enclosure: + PSF and background model). I added a warning message for background IRF. Actually I also found that there was a small typo/bug in PSF interpolation and pytest of the interpolation for full-enclosure IRF, so I also fixed it.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 73.11%. Comparing base (e097079) to head (e55286f).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1227 +/- ## ========================================== + Coverage 73.05% 73.11% +0.06% ========================================== Files 134 134 Lines 14039 14029 -10 ========================================== + Hits 10256 10258 +2 + Misses 3783 3771 -12 ```

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[moralejo]

@SeiyaNozaki, this got stuck... can you please address the comments?

[SeiyaNozaki]

Regarding DL2_to_DL3 notebook, can you re-run the notebook with this branch? @morcuended We also need to update the config file name as well. Then I got the following error when launching lstchain_create_dl3_file in this notebook. I'm not much sure what is the reason...

The metadata are not comparable
The other parameter axes data are comparable
2024-06-05 16:39:32,544 ERROR [lstchain.DataReductionFITSWriter] (tool.run): IRF files in /fefs/aswg/workspace/analysis-school-2024/DL2_to_DL3/IRF with pattern, *irf*.fits.gz are not similar and cannot be used to interpolate. Use different list of IRFs.

[morcuended]

Regarding DL2_to_DL3 notebook, can you re-run the notebook with this branch? @morcuended We also need the config file name as well. Then I got the following error when launching lstchain_create_dl3_file in this notebook. I'm not much sure what is the reason...

The metadata are not comparable
The other parameter axes data are comparable
2024-06-05 16:39:32,544 ERROR [lstchain.DataReductionFITSWriter] (tool.run): IRF files in /fefs/aswg/workspace/>analysis-school-2024/DL2_to_DL3/IRF with pattern, *irf*.fits.gz are not similar and cannot be used to interpolate. Use >different list of IRFs.

Sure, I will try it out.

Regarding the problem with the irfs, I think it is because I produced in the same directory an IRF file with different cuts or something like this. I removed the file I think is problematic. You can try again. I will do so as well.

[morcuended]

I will update the notebook as well, in my to-do list

[SeiyaNozaki]

Okay thank you @morcuended !

@chaimain @maxnoe Could you please review the code again (apart from DL2_to_DL3 notebook which will be updated by Daniel later)? Thanks!