Remove links to outdated asset library demos #25937

Job	Run time
📊 Static checks / Code style, file formatting, and docs	3m 56s
🤖 Android / Template (target=template_release)	3m 52s
🍎 macOS / Editor (target=editor, tests=yes)	4m 6s
🍎 macOS / Template (target=template_release)	3m 7s
🍏 iOS / Template (target=template_release)	2m 26s
🐧 Linux / Editor w/ Mono (target=editor)	5m 44s
🐧 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)	15m 28s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	6m 45s
🌐 Web / Template w/ threads (target=template_release, threads=yes)	4m 48s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	7m 33s
🌐 Web / Template w/o threads (target=template_release, threads=no)	4m 30s
🐧 Linux / Template w/ Mono (target=template_release)	2m 20s
🐧 Linux / Minimal template (target=template_release, everything disabled)	1m 10s
🏁 Windows / Editor (target=editor, tests=yes)	8m 38s
🏁 Windows / Template (target=template_release)	8m 0s
🪲 Godot CPP / Build and test Godot CPP	6m 47s
	1h 29m 10s

Provide feedback