Fix SkeletonModification2DLookAt with negative scales #13563

Job	Run time
📊 Static checks / Code style, file formatting, and docs	59s
🍎 macOS / Editor (target=editor, tests=yes)	39m 51s
🍎 macOS / Template (target=template_release)	30m 11s
🌐 Web / Template (target=template_release)	25m 23s
🐧 Linux / Editor w/ Mono (target=editor)	1h 8m 43s
🐧 Linux / Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=gold)	55m 35s
🤖 Android / Template (target=template_release)	43m 49s
🍏 iOS / Template (target=template_release)	25m 48s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	48m 9s
🏁 Windows / Editor (target=editor, tests=yes)	1h 32m 7s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	35m 22s
🏁 Windows / Template (target=template_release)	1h 0m 22s
🐧 Linux / Template w/ Mono (target=template_release)	36m 46s
🐧 Linux / Minimal template (target=template_release, everything disabled)	21m 24s
🪲 Godot CPP / Build and test Godot CPP	9m 55s
	9h 54m 24s

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