vmm_tests: Use 1.7 release version for servicing tests

[damanm24]

Since we have recently forked and created a 1.7 release branch, we should start using the 1.7 release in our servicing upgrade/downgrade tests. Open questions:

• [ ] Is it worth keeping the tests from the 1.6 release <--> latest?

[github-actions[bot]]

At least one Petri test failed.

[smalis-msft]

We should also update the internal guide's 'new release branch' list to mention this. That one's more complete

[github-actions[bot]]

At least one Petri test failed.

[github-actions[bot]]

At least one Petri test failed.

[github-actions[bot]]

At least one Petri test failed.