[release-5.7] LOG-4580: Add validation for secret used with the Splunk output in CLF

[openshift-cherrypick-robot]

This is an automated cherry-pick of #2194

/assign syedriko

[openshift-ci-robot]

@openshift-cherrypick-robot: Could not make automatic cherrypick of [Jira Issue LOG-4580](https://issues.redhat.com//browse/LOG-4580) for this PR as the target version is not set for this branch in the jira plugin config. Running refresh:
/jira refresh

In response to this:

This is an automated cherry-pick of #2194

/assign syedriko

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[openshift-ci-robot]

@openshift-ci-robot: This pull request references LOG-4580 which is a valid jira issue.

In response to this:

@openshift-cherrypick-robot: Could not make automatic cherrypick of [Jira Issue LOG-4580](https://issues.redhat.com//browse/LOG-4580) for this PR as the target version is not set for this branch in the jira plugin config. Running refresh:
/jira refresh

In response to this:

This is an automated cherry-pick of #2194

/assign syedriko

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[jcantrill]

/hold

for CI capacity and release of z-stream

[jcantrill]

/approve

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jcantrill, openshift-cherrypick-robot

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [jcantrill]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[syedriko]

/retest

[openshift-ci]

@openshift-cherrypick-robot: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-ocp-target-minus-one	a7088dc	link	false	/test e2e-ocp-target-minus-one
ci/prow/e2e-ocp-target-minus-two	a7088dc	link	false	/test e2e-ocp-target-minus-two

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[jcantrill]

/hold cancel
/lgtm

[jcantrill]

/lgtm