🧱 switch to new coverage collection workflows

[burgholzer]

Description

This PR switches to the new coverage collection workflow proposed in https://github.com/cda-tum/mqt-workflows/pull/2. The workflow now aggregates all coverage reports on the GitHub side before uploading to Codecov. It also uses Codecov's OIDC instead of TOKEN upload.

Checklist:

• [x] The pull request only contains commits that are related to it.
• [x] I have added appropriate tests and documentation.
• [x] I have made sure that all CI jobs on GitHub pass.
• [x] The pull request introduces no new warnings and follows the project's style guidelines.

[codecov[bot]]

Codecov Report

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

Project coverage is 91.5%. Comparing base (4a8839f) to head (196c790). Report is 108 commits behind head on main.

Additional details and impacted files

[](https://app.codecov.io/gh/cda-tum/mqt-core/pull/612?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) ```diff @@ Coverage Diff @@ ## main #612 +/- ## ===================================== Coverage 91.5% 91.5% ===================================== Files 145 145 Lines 14591 14591 Branches 2341 2341 ===================================== Hits 13364 13364 Misses 1227 1227 ``` | [Flag](https://app.codecov.io/gh/cda-tum/mqt-core/pull/612/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | Coverage Δ | | |---|---|---| | [cpp](https://app.codecov.io/gh/cda-tum/mqt-core/pull/612/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | `91.3% <ø> (ø)` | | | [python](https://app.codecov.io/gh/cda-tum/mqt-core/pull/612/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cda-tum) | `99.7% <ø> (ø)` | |