CMake writes ConfigureCommand and MakeCommand entries into
DartConfiguration.tcl when configuring a project that uses the CTest module.
These values prevented users from being able to use configure/build presets
in dashboard client mode from a pre-configured build directory.
This commit updates ctest_configure() and ctest_build() to ignore
CTEST_CONFIGURE_COMMAND / CTEST_BUILD_COMMAND when a preset is specified.
This allows the requested preset to be honored.