fix(event-handler): handle set-cookie header values with multiple attributes

[nateiler]

Summary

This fixes the scenario where a single set-cookie header value foo=bar; Max-Age=3600 is treated as two set-cookie values because multiple values may be separated by a ;.

Changes

When parsing the headers, set-cookie headers are handled using the getSetCookie method.

Logic to detect multiple header entries has been removed as multiple header values are appended to a single header (via comma).

Issue number: closes #4986

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[boring-cyborg]

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[dreamorosi]

Thank you for the PR @nateiler - appreciate it.

I have left a couple comments on the diff, would like to also get @svozza's review on the PR before we merge/

My comments were addressed, will leave to @svozza to bring the PR to merge state.

[svozza]

Thank you @nateiler for your work on this. Approved.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
4.0% Duplication on New Code

See analysis details on SonarQube Cloud

[boring-cyborg]

Awesome work, congrats on your first merged pull request and thank you for helping improve everyone's experience!