Inspector: Fix clearing array/dictionary element with `<Object#null>` #16955

Job	Run time
📊 Static checks / Code style, file formatting, and docs	33s
🍏 iOS / Template (target=template_release)	3m 5s
🐧 Linux / Editor w/ Mono (target=editor)	2m 58s
🍎 macOS / Editor (target=editor, tests=yes)	40m 47s
🐧 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)	12m 6s
🍎 macOS / Template (target=template_release)	24m 5s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	5m 47s
🌐 Web / Template (target=template_release)	1m 3s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	5m 49s
🤖 Android / Template (target=template_release)	3m 35s
🐧 Linux / Template w/ Mono (target=template_release)	1m 5s
🐧 Linux / Minimal template (target=template_release, everything disabled)	54s
🏁 Windows / Editor (target=editor, tests=yes)	8m 39s
🏁 Windows / Template (target=template_release)	5m 33s
🪲 Godot CPP / Build and test Godot CPP	6m 50s
	2h 2m 49s

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