tests/channels/pjsip/message: Add out-of-dialog Contact stripping test

[AlexisHadj]

This new test verifies that Asterisk correctly strips the Contact header from outbound MESSAGE requests, as required by RFC 3428.

1-Added SIPp scenarios to send and receive MESSAGEs with inverse
validation on the Contact header.
2-Added Asterisk configuration (pjsip.conf, extensions.conf) to
support the test.
3-Registered the new test in the pjsip message test suite.

Note: This test is associated with the change in Pull Request #1729

[AlexisHadj]

Note: This test is associated with the change in Pull Request #1729 therefore should be merged after Pull Request #1729 . That is the reason master-gates check fails with ".....Regexp matched but should not....""

[github-actions]

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[github-actions]

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