fix: add missing job affinity field to spark applications

[razvan]

Description

Fixes #639

✔️ : CI https://testing.stackable.tech/view/02%20Operator%20Tests%20(custom)/job/spark-k8s-operator-it-custom/64/

Also local tests:

--- PASS: kuttl (2185.13s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/pyspark-ny-public-s3_openshift-false_spark-4.1.1 (320.22s)
        --- PASS: kuttl/harness/logging_openshift-false_spark-logging-4.1.1_ny-tlc-report-0.3.0 (595.01s)
        --- PASS: kuttl/harness/smoke_openshift-false_spark-4.1.1_s3-use-tls-true (279.77s)
        --- PASS: kuttl/harness/spark-ny-public-s3_openshift-false_spark-4.1.1_s3-use-tls-true (165.08s)
        --- PASS: kuttl/harness/delta-lake_openshift-false_spark-delta-lake-4.0.1 (586.17s)
        --- PASS: kuttl/harness/spark-connect_openshift-false_spark-connect-4.1.1_s3-use-tls-true (427.90s)
        --- PASS: kuttl/harness/pyspark-ny-public-s3-image_openshift-false_spark-4.1.1_ny-tlc-report-0.3.0 (170.30s)
        --- PASS: kuttl/harness/spark-history-server_openshift-false_spark-4.1.1_s3-use-tls-true (223.40s)
        --- PASS: kuttl/harness/resources_openshift-false_spark-4.1.1 (110.60s)
        --- PASS: kuttl/harness/spark-pi-private-s3_openshift-false_spark-4.1.1 (139.31s)
        --- PASS: kuttl/harness/iceberg_openshift-false_spark-iceberg-4.0.1 (93.47s)
        --- PASS: kuttl/harness/spark-examples_openshift-false_spark-4.1.1 (62.70s)
        --- PASS: kuttl/harness/overrides_openshift-false_spark-4.1.1 (167.25s)
        --- PASS: kuttl/harness/hbase-connector_openshift-false_spark-hbase-connector-3.5.8_hbase-2.6.4_hdfs-latest-3.4.2_zookeeper-latest-3.9.4 (629.30s)
        --- PASS: kuttl/harness/custom-log-directory_openshift-false_spark-4.1.1_hdfs-latest-3.4.2_zookeeper-latest-3.9.4 (201.63s)
PASS

[adwk67]

LGTM