Rework viewport capture in preview generation #23372

Job	Run time
📊 Static checks / Code style, file formatting, and docs	32s
🍎 macOS / Editor (target=editor, tests=yes)	9m 18s
🍏 iOS / Template (target=template_release)	3m 9s
🍎 macOS / Template (target=template_release)	4m 4s
🤖 Android / Template (target=template_release)	4m 31s
🐧 Linux / Editor w/ Mono (target=editor)	6m 39s
🌐 Web / Template w/ threads (target=template_release, threads=yes)	4m 32s
🐧 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)	16m 53s
🏁 Windows / Editor (target=editor, tests=yes)	9m 26s
🌐 Web / Template w/o threads (target=template_release, threads=no)	4m 23s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	7m 24s
🏁 Windows / Template (target=template_release)	7m 40s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	7m 52s
🐧 Linux / Template w/ Mono (target=template_release)	2m 15s
🐧 Linux / Minimal template (target=template_release, everything disabled)	1m 57s
🪲 Godot CPP / Build and test Godot CPP	7m 1s
	1h 37m 36s

Provide feedback