RUBY-3361 Test x509 authentication on Atlas

[comandeo-mongo]

No description provided.

[Copilot]

Pull Request Overview

This PR refactors Atlas connectivity tests to support X.509 authentication testing alongside existing regular authentication methods. The changes replace the old single-purpose operations test with a comprehensive connectivity test suite that can handle multiple authentication mechanisms.

• Replaces single ping test with structured connectivity tests for regular and X.509 authentication
• Adds support for X.509 certificate-based authentication using base64-encoded certificates
• Updates CI configuration to pass all necessary Atlas environment variables for both authentication types

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
spec/atlas/operations_spec.rb	Removed - old single-purpose ping test
spec/atlas/atlas_connectivity_spec.rb	Enhanced with shared examples and X.509 authentication support
.evergreen/run-tests-atlas.sh	Simplified by removing custom test status handling
.evergreen/config/standard.yml.erb	Updated task name and display name for clarity
.evergreen/config/common.yml.erb	Added X.509 environment variables and removed old task group
.evergreen/config.yml	Same changes as common.yml.erb applied to generated config

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[alcaeus]

Code LGTM from what I can see. Happy to merge if the connectivity tests pass.