Extra facets added for EMAC to map o3, tro3 and aps

[FranziskaWinterstein]

Description

This pull request introduces extra facets in emac-mappings.yml so that the variables for O3 (o3 and tro3) are found. This makes it also possible to apply the derived variable toz.

Checklist

It is the responsibility of the author to make sure the pull request is ready to review. The icons indicate whether the item will be subject to the 🛠 Technical or 🧪 Scientific review.

• [x] 🧪 The new functionality is relevant and scientifically sound
• [x] 🛠 This pull request has a descriptive title and labels
• [x] 🛠 Code is written according to the code quality guidelines
• [x] 🧪 and 🛠 Documentation is available
• [x] 🛠 Unit tests have been added
• [x] 🛠 Changes are backward compatible
• [x] 🛠 Any changed dependencies have been added or removed correctly
• [x] 🛠 The list of authors is up to date
• [x] 🛠 All checks below this pull request were successful

[codecov[bot]]

Codecov Report

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

Project coverage is 94.70%. Comparing base (ecb01b3) to head (baf0fd6). Report is 44 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2501 +/- ## ======================================= Coverage 94.70% 94.70% ======================================= Files 249 249 Lines 14114 14114 ======================================= Hits 13367 13367 Misses 747 747 ```

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