Fixes https://github.com/twentyhq/twenty/issues/11864 and
https://github.com/twentyhq/core-team-issues/issues/908
We should not send `createManyXXX` mutations with FE-forged ids in the
payload if we want to do an upsert, because that 1) prevents records
from being merged 2) triggers optimistic rendering while we can't know
before-hand which records will actually be created and which records
will only be updated
Also noticed createdBy was being overriden even for records we are
updating and not creating, which did not seem right, so fixed that too
f782f4dcd8