FLINK-36551: [OLM] ensure that docker-entry.sh actually replaces the keystore pod volume

[k-wall]

What is the purpose of the change

This pull request fixes a defect (FLINK-36551) in tools/olm/docker_entry.sh. In order for Flink Kubernetes Operator to function under OLM the webhook utilises a serving certificate provided by OLM. docker_entry.sh rewrites the deployment to allow this substitution to occur.

Unfortunately, docker_entry.sh makes an assumption about the index of the keystore volume within the deployment. The index has changed over time, meaning docker_entry.sh replaces the wrong volume entry. This leads to a volume with a duplicate name. The CSV fails to be become ready as a result.

Brief change log

• [OLM] Fix indexing error when replacing the keystore volume within CSV.

Verifying this change

I manually verified the change, firstly by ensuring the yq command was having the right effect and secondly by generating a OLM using generate-olm-bundle.sh.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changes to the CustomResourceDescriptors: no
• Core observer or reconciler logic that is regularly executed: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[SamBarker]

LGTM

I've replicated the original issues, as it leads to a failed install plan, and have verified this PR fixes it.