fix(csharp): emit component_type.o for linker

The `map<K, V>` WIT syntax is a gated feature that the default wit-parser
used by wasm-component-ld's `--component-type` flag cannot parse, so the
text-based component type path was blocking any world that uses maps.
Switching to the same object-file approach already used by the C and C++
backends lets the component type flow through as a custom section without
round-tripping through the text parser.

Signed-off-by: Yordis Prieto <[email protected]>

Author: yordis