Fix polkadot zombienet tests (#1276)

* fix tests

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* ZOMBIENET_INTEGRATION_TEST_SECONDARY_IMAGE

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* deleted by mistake

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* remove LOCAL_DIR override

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* Fix secondary image

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* fix get BUILD_RELEASE_VERSION in pipeline

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Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>
Co-authored-by: Javier Viola <javier@parity.io>