The container image already defines the user and the email for the
builder's/CI's git operations[1] so there is no need to override it here
and have to maintain two places for this identity.

[1]https://gitlab.eclipse.org/eclipse/oniro-core/oniro/-/blob/kirkstone/.oniro-ci/containers/bitbake-builder/Dockerfile

Fixes eclipse/oniro-core/oniro#513



Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>