add upgrade connector tests

[arihant-confluent]

Problem

Solution

Does this solution apply anywhere else?

• [ ] yes
• [ ] no

If yes, where?

Test Strategy

Testing done:

• [ ] Unit tests
• [ ] Integration tests
• [ ] System tests
• [ ] Manual tests

Release Plan

[cla-assistant[bot]]

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1 out of 2 committers have signed the CLA.

:white_check_mark: amitr17
:x: arihant-confluent
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