Update GitHub action LLVM version to 17.0.5

[jonwis]

In #1372 it looks like the build VMs were updated to a more recent VS and VCRT and STL combination, requiring an updated LLVM toolchain. This bumps the target LLM version to match.

[jonwis]

A new and interesting errro!

[jonwis]

Turns out that LLVM 17.0.5 resolved this complaint:

cppwinrt/test/test_cpp20/custom_error.cpp

Lines 38 to 42 in bf4459b

	#if defined(__clang__) && defined(_MSC_VER)
	// FIXME: Blocked on __cpp_consteval, see:
	// * https://github.com/microsoft/cppwinrt/pull/1203#issuecomment-1279764927
	// * https://github.com/llvm/llvm-project/issues/57094
	TEST_CASE("custom_error_logger", "[!shouldfail]")

... so the test metadata needs to be updated to say that clang is no longer "!shouldfail"

[jonwis]

Notably, the test_component component does not build correctly here:

msbuild /m /p:Configuration=Debug,Platform=x64,Clang=1,LLVMToolsVersion=17.0.5,LLVMInstallDir=C:\llvm cppwinrt.sln

At least on my machine, the test_component.vcxproj picks up C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\Llvm\x64\bin\clang-cl.exe ... everything else correctly picks up the $(SolutionRootDir).llvm path. This causes a series of errors in yvals_core.h due to undefined uintptr_t

A problem for another day.