update DrawSelectionLine, drop deprecated GL_LINE_STIPPLE #1130

Job	Run time
prepare	9s
prepare-static-dependencies	29s
build-macos (macos-26-arm)	59s
build-macos (macos-15-intel)	3m 14s
build-macos (macos-26-arm-static-link)	1m 32s
build-macos (macos-26-intel-cross-compile-static-link)	1m 40s
build-windows (windows-x64-avx2)	3m 30s
build-linux (ubuntu-22)	2m 22s
build-windows (windows-2025)	4m 4s
build-windows (windows-x64-no-simd)	3m 37s
build-windows (windows-arm64)	4m 10s
build-windows (windows-x86-sse2)	3m 32s
build-linux (ubuntu-26)	2m 2s
build-linux (ubuntu-arm-static-link)	2m 42s
build-linux (ubuntu-24)	2m 10s
build-linux (ubuntu-static-link)	3m 6s
	39m 18s

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