channels/pjsip: Add tests for SIP MESSAGE redirect functionality

[maximilianfridrich]

This commit adds comprehensive test coverage for SIP MESSAGE redirect handling with 305 Use Proxy responses in Asterisk's PJSIP stack.

Test coverage includes:

• Basic MESSAGE redirect with follow_redirect_methods=message configured
• Verification that redirects are NOT followed when follow_redirect_methods is unset
• Multiple Contact header handling with q-value priority
• Contact failover when higher-priority contacts reject (4xx responses)
• Redirect loop detection and prevention

[github-actions]

Pull Request Checklist Complete

[github-actions]

Workflow PRCheck failed
master-gates: FAILED TEST: channels/pjsip/message/message_redirect
master-gates: FAILED TEST: channels/pjsip/message/message_redirect_multiple

[maximilianfridrich]

The two new message/message_redirect* tests that failed are exactly the ones that I would expect to fail without the new Asterisk improvement. The tests pass in the corresponding Asterisk PR with the redirect improvement which uses this testsuite PR: asterisk/asterisk#1580 (link to corresponding job).

[maximilianfridrich]

cherry-pick-to: 20
cherry-pick-to: 22
cherry-pick-to: 23

[gtjoseph]

I probably forgot to announce this but you can now add asterisk-test-pr: <pr> to testsuite PRs just like you added testsuite-test-pr to your asterisk PR. I'll update your comment.

Pull Request Checklist Complete

[github-actions]

Workflow PRCheck completed successfully

[maximilianfridrich]

Updated in accordance with the Asterisk PR - the redirect feature is now configured using the new pjsip endpoint option follow_redirect_methods.

[github-actions]

Workflow PRCheck completed successfully

[maximilianfridrich]

@gtjoseph Do you think this PR could be merged? The corresponding Asterisk PR has been merged.

[gtjoseph]

@gtjoseph Do you think this PR could be merged? The corresponding Asterisk PR has been merged.

Yeah sorry. I really need to set up the scripts so that the testsuite PR automatically merges when the asterisk PR does.

done

[github-actions]

Workflow PRCPCheck completed successfully

[github-actions]

Successfully merged to branch master and cherry-picked to ["20","22","23"]