[release-1.11] Fix KeyError in require_stdlib for non-stdlib extensions #60491

IanButterworth merged 2 commits intoJuliaLang:backports-release-1.11JuliaLang/julia:backports-release-1.11from

IanButterworth:ib/1.11_fix_require_stdlibIanButterworth/julia:ib/1.11_fix_require_stdlibCopy head branch name to clipboard