Update TLS test matrix

[ReToCode]

Fixes #15393.

Proposed Changes

• Limit system-internal-tls tests to kourier/contour
• Limit cluster-local-domain-tls tests to kourier/istio/contour

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.60%. Comparing base (2156812) to head (f1ee782).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15394      +/-   ##
==========================================
+ Coverage   84.58%   84.60%   +0.02%     
==========================================
  Files         219      219              
  Lines       13587    13587              
==========================================
+ Hits        11492    11495       +3     
+ Misses       1726     1725       -1     
+ Partials      369      367       -2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ReToCode]

/assign @dprotaso

[ReToCode]

/assign @skonto

[dprotaso]

/lgtm
/approve

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dprotaso, ReToCode

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [ReToCode,dprotaso]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment