Unnecessary include in libbson bson-endian.h

The inclusion of bson-types.h was introduced in https://github.com/mongodb/libbson/commit/fc825f569d7ad6158682f11503f53543d105426a. However, https://github.com/mongodb/libbson/commit/c14f75eadf3d9353e754165f31d9d2e1b5e7d70e removed the need for it, but it was not removed. This causes the unavailability of bson-endian.h macros if they are needed in bson-types.h.