Fix `AnimationNodeTransition` with negative time scale #6319

Job	Run time
📊 Static checks / Code style, file formatting, and docs	36s
🍏 iOS / Template (target=template_release)	2m 24s
🍎 macOS / Editor (target=editor, tests=yes)	5m 36s
🍎 macOS / Template (target=template_release)	4m 51s
🐧 Linux / Editor w/ Mono (target=editor)	4m 3s
🐧 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)	24m 29s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	7m 58s
🐧 Linux / Template w/ Mono (target=template_release)	1m 21s
🐧 Linux / Minimal template (target=template_release, everything disabled)	1m 0s
🤖 Android / Template (target=template_release)	5m 6s
🌐 Web / Template (target=template_release)	1m 32s
🏁 Windows / Editor (target=editor, tests=yes)	11m 26s
🏁 Windows / Template (target=template_release)	8m 46s
	1h 19m 8s

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