ProjectExplorer: Avoid assert on setup without a clang binary

Having no clang binary is a valid setup and should not assert.

Change-Id: Ifc3065d35e546452b0919bfda47e85d9cf2ce79f
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/gcctoolchain.cpp

@@ -1629,7 +1629,6 @@ FilePath GccToolchainFactory::correspondingCompilerCommand(
 Toolchains GccToolchainFactory::autoDetectSdkClangToolchain(const Toolchains &known)
 {
     const expected_str<FilePath> compilerPath = Core::ICore::clangExecutable(CLANG_BINDIR);
-    QTC_CHECK_EXPECTED(compilerPath);
     if (!compilerPath)
         return {};