fix/set object type correctly

[pljakobs]

the rgbww sample app used
auto req = update.toColor().params.toRaw(); and similar calls
to set the params enum to the correct type.
However, in the chained call, that was only applied to a temporary object, leading to a segfault when writing to it.
this fix changes this as follows, creating a real object and setting it's type correctly.

		auto colorObject = update.toColor();
		auto req = colorObject.params.toRaw();

[mikee47]

Good catch. It would be nice if there were a way to get the compiler to catch this sort of problem!

[pljakobs]

indeed, I assume the segfault is a blessing in this case, it could also have happened silently if the written datatype had fit into the memory location.

[mikee47]

NB. If you build with ENABLE_SANITIZERS=1 it'll catch this sort of thing: I must remember to do that more often!