Make retarget keep global rest of unmapped bones if there are no mapped bones on the child #29668

Job	Run time
📊 Static checks / Code style, file formatting, and docs	36s
🐧 Linux / Editor w/ Mono (target=editor)	34m 44s
🤖 Android / Template (target=template_release)	25m 39s
🐧 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)	41m 19s
🍎 macOS / Editor (target=editor, tests=yes)	27m 2s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	30m 52s
🍎 macOS / Template (target=template_release)	16m 0s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	28m 21s
🐧 Linux / Template w/ Mono (target=template_release)	20m 3s
🍏 iOS / Template (target=template_release)	8m 21s
🌐 Web / Template w/ threads (target=template_release, threads=yes)	19m 49s
🐧 Linux / Minimal template (target=template_release, everything disabled)	13m 50s
🌐 Web / Template w/o threads (target=template_release, threads=no)	20m 5s
🏁 Windows / Editor (target=editor, tests=yes)	42m 23s
🏁 Windows / Template (target=template_release)	29m 14s
🪲 Godot CPP / Build and test Godot CPP	7m 18s
	6h 5m 36s

Provide feedback