e2e-tests: Connect to VM without SSH key

[adombeck]

The SSH public key setup made things complex and caused the tests to fail on Dependabot PRs because the CI secrets are not available there.

Let's simplify things and just allow SSH connections to the VM without an SSH key or password.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.59%. Comparing base (0297aa8) to head (eb22839).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1245      +/-   ##
==========================================
+ Coverage   80.57%   87.59%   +7.02%     
==========================================
  Files          20       91      +71     
  Lines         978     6231    +5253     
  Branches        0      111     +111     
==========================================
+ Hits          788     5458    +4670     
- Misses        190      717     +527     
- Partials        0       56      +56     

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