Remove noexcept specifier from CreatureCustomData move ctor

C++17 doesn't allow to declare defaulted move ctor with not matching
exception specification to the calculated one:
/Users/eddie/Downloads/BUILD/openmw-master/apps/openmw/mwclass/creature.cpp:63:9: error:
      exception specification of explicitly defaulted move constructor does not
      match the calculated one
        CreatureCustomData(CreatureCustomData&& other) noexcept = default;
        ^

http://wg21.link/p1286r2 makes this possible in C++20 and newer compilers
already have it working even with -std=c++17 but older onces give an error.

apps/openmw/mwclass/creature.cpp

@@ -60,7 +60,7 @@ namespace MWClass
 
         CreatureCustomData() = default;
         CreatureCustomData(const CreatureCustomData& other);
-        CreatureCustomData(CreatureCustomData&& other) noexcept = default;
+        CreatureCustomData(CreatureCustomData&& other) = default;
 
         CreatureCustomData& asCreatureCustomData() override
         {