Compiler warnings

[Tishj]

/__w/duckdb/duckdb/build/release/_deps/iceberg_extension_fc-src/src/include/iceberg_types.hpp: In function ‘std::string duckdb::IcebergManifestContentTypeToString(duckdb::IcebergManifestContentType)’:
Warning: /__w/duckdb/duckdb/build/release/_deps/iceberg_extension_fc-src/src/include/iceberg_types.hpp:30:1: warning: control reaches end of non-void function [-Wreturn-type]
   30 | }
      | ^
/__w/duckdb/duckdb/build/release/_deps/iceberg_extension_fc-src/src/include/iceberg_types.hpp: In function ‘std::string duckdb::IcebergManifestEntryStatusTypeToString(duckdb::IcebergManifestEntryStatusType)’:
Warning: /__w/duckdb/duckdb/build/release/_deps/iceberg_extension_fc-src/src/include/iceberg_types.hpp:43:1: warning: control reaches end of non-void function [-Wreturn-type]
   43 | }
      | ^
/__w/duckdb/duckdb/build/release/_deps/iceberg_extension_fc-src/src/include/iceberg_types.hpp: In function ‘std::string duckdb::IcebergManifestEntryContentTypeToString(duckdb::IcebergManifestEntryContentType)’:
Warning: /__w/duckdb/duckdb/build/release/_deps/iceberg_extension_fc-src/src/include/iceberg_types.hpp:56:1: warning: control reaches end of non-void function [-Wreturn-type]
   56 | }

Probably want to add a default: throw InternalException(...) to silence these warnings