make description of SetOem ParameterType23 more clear

Current documentation could be interpreted in such a way, that application can use ParameterType23 to modify the I&M0 data of API 0 handled by protocol stack. However, that is not the intention or purpose.

Instead, this service is used to configure an additional I&M0 dataset for a profile application which uses a submodule with API != 0. This needs to be made clear in documentation (maybe by giving an example plus explicitly stating this service does not modify the content of I&M0 for API 0).