fix(session): do not expect current schema to be changed when finding space

Sometimes, we had an issue where some data could not be pushed to the ETP Server. After investigation, this was due to a failing assertion in Session.cpp: ../../src/lib/oes/eml/openkv/Session.cpp(199): Assertion failed: set_current_schema_ok

This assertion initially intended toa ssert that we correctly set the current_schema when looking for a given space. But actually, set_current_schema() returns true if the current_schema changed. (And false if it is not, whether it is because of an error or not, we don't differentiate...).

So I removed this assertion which was blocking more than anything else.