Revert "Add light_curve.embed: Astromer ONNX embedding models"

[hombit]

This reverts commit f8ba4cd, which I accidentally pushed to main in #696

[codspeed-hq]

Merging this PR will not alter performance

✅ 106 untouched benchmarks
⏩ 106 skipped benchmarks¹

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_{Comparing revert-embed-from-main (c3bf8de) with main (9ee9f48)²}

Footnotes

1. 106 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (c3bf8de) during the generation of this report, so 9ee9f48 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩