FIX: Fix ‘map’ in namespace ‘std’ does not name a template type

/run/build/BambuStudio/src/libslic3r/FilamentMixer.hpp:152:6: error: ‘map’ in namespace ‘std’ does not name a template type
  152 | std::map<std::string, std::string> validate_mixed_filament_params(
      |      ^~~
/run/build/BambuStudio/src/libslic3r/FilamentMixer.hpp:9:1: note: ‘std::map’ is defined in header ‘<map>’; this is probably fixable by adding ‘#include <map>’
    8 | #include <vector>
  +++ |+#include <map>
    9 |