Support importing 1/2/4-bpp BMP images of size non-divisible by 8/4/2 #172

Job	Run time
📊 Static checks / Code style, file formatting, and docs	36s
🍎 macOS / Editor (target=editor, tests=yes)	31m 9s
🍎 macOS / Template (target=template_release)	25m 35s
🤖 Android / Editor (target=editor)	24m 58s
🐧 Linux / Editor w/ Mono (target=editor)	40m 58s
🤖 Android / Template arm32 (target=template_release, arch=arm32)	16m 25s
🐧 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 38s
🍏 iOS / Template (target=template_release)	1m 25s
🤖 Android / Template arm64 (target=template_release, arch=arm64)	18m 5s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	38m 9s
🌐 Web / Template w/ threads (target=template_release, threads=yes)	26m 24s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	7m 13s
🌐 Web / Template w/o threads (target=template_release, threads=no)	25m 44s
🏁 Windows / Editor (target=editor, tests=yes)	48m 50s
🐧 Linux / Template w/ Mono (target=template_release)	2m 13s
🐧 Linux / Minimal template (target=template_release, everything disabled)	1m 2s
🏁 Windows / Template (target=template_release)	35m 36s
🪲 Godot CPP / Build and test Godot CPP	1m 37s
	6h 37m 37s

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