fix: link to jar file without the stackable qualifier

[razvan]

Description

The introduction for stackable${RELEASE} qualifiers to jar names causes problems with Spark Connect since the operator needs to specifically reference the jar file when creating the Spark cluster. See this line in the operator.

This PR adds a symbolic link to the jar file using the "original" artifact name"

❯ docker run --rm -ti oci.stackable.tech/sdp/spark-k8s:3.5.6-stackable0.0.0-dev  bash
stackable@20bd20b12edb /stackable/spark $ ll connect/ | grep spark-connect_2.12
-rw-rw-r--. 1 stackable root 14148220 Jun 23 13:42 spark-connect_2.12-3.5.6-stackable0.0.0-dev.jar
lrwxrwxrwx. 1 stackable root       47 Jun 23 13:42 spark-connect_2.12-3.5.6.jar -> spark-connect_2.12-3.5.6-stackable0.0.0-dev.jar

Also the block gathering the connect jars has been moved up right after the Spark build step.

Tests results:

--- PASS: kuttl (78.94s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/spark-connect_openshift-false_spark-connect-3.5.6_spark-connect-client-3.5.6 (78.48s)
PASS

Definition of Done Checklist

Note

Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant.

Please make sure all these things are done and tick the boxes

• Changes are OpenShift compatible
• All added packages (via microdnf or otherwise) have a comment on why they are added
• Things not downloaded from Red Hat repositories should be mirrored in the Stackable repository and downloaded from there
• All packages should have (if available) signatures/hashes verified
• Add an entry to the CHANGELOG.md file
• Integration tests ran successfully

TIP: Running integration tests with a new product image

The image can be built and uploaded to the kind cluster with the following commands:

bake --product <product> --image-version <stackable-image-version>
kind load docker-image <image-tagged-with-the-major-version> --name=<name-of-your-test-cluster>

See the output of bake to retrieve the image tag for <image-tagged-with-the-major-version>.