Fix: namespace-create have kubectl in path

[ktsakalozos]

What this PR does / why we need it: In juju deployed clusters namespace-create action is failing

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes https://github.com/juju-solutions/bundle-canonical-kubernetes/issues/326

Special notes for your reviewer:

Release note:

[k8s-ci-robot]

Hi @ktsakalozos. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

I understand the commands that are listed here.

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.

[Cynerva]

/ok-to-test

[Cynerva]

/assign @Cynerva

[Cynerva]

/lgtm

This looks good, thanks

[Cynerva]

/approve no-issue

[k8s-github-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Cynerva, ktsakalozos

Associated issue requirement bypassed by: Cynerva

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

Needs approval from an approver in each of these OWNERS Files:

• cluster/juju/OWNERS [Cynerva,ktsakalozos]

You can indicate your approval by writing /approve in a comment
You can cancel your approval by writing /approve cancel in a comment

[Cynerva]

/retest

[Cynerva]

/retest

[Cynerva]

/retest

[k8s-github-robot]

Automatic merge from submit-queue (batch tested with PRs 48439, 48440, 48394)