ci: use 3 replicas for no-vnet E2E jobs

[jackfrancis]

Reason for Change:

This PR ensures we're testing w/ more than one coredns pod on all E2E tests (containerd tests currently re-use the no-vnet cluster config)

Issue Fixed:

Credit Where Due:

Does this change contain code from or inspired by another project?

• No
• Yes

If "Yes," did you notify that project's maintainers and provide attribution?

• No
• Yes

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• tested upgrade from previous version

Notes:

[acs-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jackfrancis

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• OWNERS [jackfrancis]

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[codecov]

Codecov Report

Merging #4061 (855b876) into master (540f3e6) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #4061   +/-   ##
=======================================
  Coverage   73.23%   73.23%           
=======================================
  Files         135      135           
  Lines       20640    20640           
=======================================
  Hits        15115    15115           
  Misses       4549     4549           
  Partials      976      976           

Impacted Files	Coverage Δ
pkg/engine/templates_generated.go	43.70% <0.00%> (ø)

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