Fix nodes receiving mouse events in black bars of `Window` #8116

Job	Run time
📊 Static checks / Code style, file formatting, and docs	1m 7s
🍏 iOS / Template (target=template_release)	27m 5s
🌐 Web / Template (target=template_release)	23m 14s
🍎 macOS / Editor (target=editor, tests=yes)	47m 28s
🍎 macOS / Template (target=template_release)	28m 40s
🤖 Android / Template (target=template_release)	54m 6s
🏁 Windows / Editor (target=editor, tests=yes)	1h 24m 46s
🏁 Windows / Template (target=template_release)	47m 57s
🐧 Linux / Editor w/ Mono (target=editor)	1h 18m 21s
🐧 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)	51m 3s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	41m 38s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	34m 36s
🐧 Linux / Template w/ Mono (target=template_release)	37m 29s
🐧 Linux / Minimal template (target=template_release, everything disabled)	21m 1s
🪲 Godot CPP / Build and test Godot CPP	9m 52s
	9h 48m 23s

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