Feature/e2e test ca cert

[voluntas]

This pull request includes several updates to the end-to-end (E2E) testing workflow and adds a new test for CA certificates. The changes mainly focus on improving the testing process and adding new functionalities.

E2E Workflow Improvements:

• Reduced the timeout for E2E tests from 30 minutes to 15 minutes in the e2e_test_ubuntu, e2e_test_macos, and e2e_test_windows jobs in .github/workflows/e2e-test.yml. [1] [2] [3]
• Added a new test step for test_ca_cert.py to the E2E test jobs in .github/workflows/e2e-test.yml. [1] [2] [3]

New CA Certificate Test:

• Introduced a new test file tests/test_ca_cert.py to verify the validity of CA certificates used by Sora. This test checks the connection using Let's Encrypt and Google PKI certificates.
• Updated the Sendonly class in tests/client.py to include an optional ca_cert parameter for CA certificate validation. [1] [2]

Test Refactoring:

• Simplified the test_signaling_message in tests/test_signaling_message.py by removing random audio and video selection and always setting them to True. [1] [2]