Fix particle id guessing when loading data

[mikael10j]

removes the casting to set of the array of mc_particle as set is not subscriptable

[codecov[bot]]

Codecov Report

Patch coverage: 31.61% and project coverage change: +0.12 :tada:

Comparison is base (eafbe37) 63.15% compared to head (b0140f4) 63.27%.

:exclamation: Current head b0140f4 differs from pull request most recent head 0c2467a. Consider uploading reports for the commit 0c2467a to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #195 +/- ## ========================================== + Coverage 63.15% 63.27% +0.12% ========================================== Files 21 20 -1 Lines 2717 2715 -2 ========================================== + Hits 1716 1718 +2 + Misses 1001 997 -4 ``` | [Impacted Files](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory) | Coverage Δ | | |---|---|---| | [ctaplot/gammaboard/reader.py](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory#diff-Y3RhcGxvdC9nYW1tYWJvYXJkL3JlYWRlci5weQ==) | `0.00% <0.00%> (ø)` | | | [ctaplot/plots/style.py](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory#diff-Y3RhcGxvdC9wbG90cy9zdHlsZS5weQ==) | `100.00% <ø> (ø)` | | | [ctaplot/gammaboard/gammaboard.py](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory#diff-Y3RhcGxvdC9nYW1tYWJvYXJkL2dhbW1hYm9hcmQucHk=) | `11.86% <2.24%> (-0.05%)` | :arrow_down: | | [ctaplot/ana/ana.py](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory#diff-Y3RhcGxvdC9hbmEvYW5hLnB5) | `88.08% <86.66%> (-0.15%)` | :arrow_down: | | [ctaplot/ana/tests/test\_ana.py](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory#diff-Y3RhcGxvdC9hbmEvdGVzdHMvdGVzdF9hbmEucHk=) | `100.00% <100.00%> (ø)` | | | [ctaplot/plots/plots.py](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory#diff-Y3RhcGxvdC9wbG90cy9wbG90cy5weQ==) | `78.46% <100.00%> (ø)` | | | [ctaplot/plots/tests/test\_plots.py](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory#diff-Y3RhcGxvdC9wbG90cy90ZXN0cy90ZXN0X3Bsb3RzLnB5) | `98.73% <100.00%> (+0.07%)` | :arrow_up: | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/cta-observatory/ctaplot/pull/195/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cta-observatory)

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