Clear sub-resources list when no sub-resource exists #597

Job	Run time
📊 Static checks / Code style, file formatting, and docs	2m 30s
🍎 macOS / Editor (target=editor, tests=yes)	11m 47s
🍎 macOS / Template (target=template_release)	13m 54s
🍏 iOS / Template (target=template_release)	18m 39s
🤖 Android / Template (target=template_release)	23m 28s
🌐 Web / Template (target=template_release)	1m 57s
🏁 Windows / Editor (target=editor, tests=yes)	34m 24s
🏁 Windows / Template (target=template_release)	24m 19s
🐧 Linux / Editor w/ Mono (target=editor)	28m 48s
🐧 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)	26m 17s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	25m 28s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	22m 53s
🐧 Linux / Template w/ Mono (target=template_release)	1m 52s
🐧 Linux / Minimal template (target=template_release, everything disabled)	2m 16s
🪲 Godot CPP / Build and test Godot CPP	6m 43s
	4h 5m 15s

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