[release-1.32] Fix: Preserve Whitespace for Tag Values Resembling "null" to Prevent ARM Assignment Errors

[k8s-infra-cherrypick-robot]

This is an automated cherry-pick of #8071

/assign nilo19

Tags with values resembling "null" (e.g., " null " or " NuLL ") will now retain their leading and trailing whitespace during inheritance or updates to avoid errors caused by ARM's reserved tag value "null". 
This change only affects tags with such specific values, ensuring all other tags continue to have whitespace trimmed as before.

[nilo19]

/kind bug

[nilo19]

/ok-to-test

[coveralls]

coverage: 74.26% (+0.008%) from 74.252%
when pulling 25f6858 on k8s-infra-cherrypick-robot:cherry-pick-8071-to-release-1.32
into b0312a1 on kubernetes-sigs:release-1.32.

[nilo19]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: k8s-infra-cherrypick-robot, nilo19

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 [nilo19]

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

[nilo19]

/retest

[nilo19]

/retest