[release-1.28] Add Istio 1.28.3 + bump operator version

[rafaelvzago]

What type of PR is this?

• Enhancement / New Feature
• Bug Fix
• Refactor
• Optimization
• Test
• Documentation Update

What this PR does / why we need it:

This PR prepares the release-1.28 branch for Istio 1.28.3:

• Bumps operator VERSION to 1.28.3
• Updates PREVIOUS_VERSION to 1.28.2
• Removes alpha/development versions from versions.yaml (master, v1.30-alpha)
• Regenerates manifests, charts, and bundle files

Which issue(s) this PR fixes:

Fixes #1532

Related Issue/PR #1533

Additional information:

This follows the standard release preparation process for adding a new Istio patch version to the operator.

[istio-testing]

Hi @rafaelvzago. Thanks for your PR.

I'm waiting for a istio-ecosystem or istio member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.94%. Comparing base (f9d93a6) to head (defc78b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1542      +/-   ##
==========================================
+ Coverage   80.77%   80.94%   +0.17%     
==========================================
  Files          44       44              
  Lines        2299     2299              
==========================================
+ Hits         1857     1861       +4     
+ Misses        324      322       -2     
+ Partials      118      116       -2     

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