Update dockerfile to add TARGETARCH

[varshab1210]

What type of PR is this?

/kind enhancement

What does this PR do / why we need it:

Helps build the image compatible with both x86 and ARM64.
Assisted by cursor.

Have you updated the necessary documentation?

• Documentation update is required by this PR.
• Documentation has been updated.

Which issue(s) this PR fixes:

Fixes #?

Test acceptance criteria:

• Unit Test
• E2E Test

How to test changes / Special notes to the reviewer:

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[varshab1210]

/test v4.19-kuttl-parallel
/test v4.19-images
/test unit

[varshab1210]

/retest

[svghadi]

/lgtm
/approve

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: svghadi

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