Fix content filtering on Windows with modern Connext DDS (backport #226)

[mergify]

Description

This PR fixes Content Filtering on Windows when using modern versions of RTI Connext DDS (6.x and 7.x).

The Problem

Previously, the rmw_connextdds implementation on Windows was forced into a "Compatibility Mode." This mode:

1. Disabled Writer-side filtering: All samples were sent to all matching readers, regardless of whether they matched the filter.
2. Forced Reader-side filtering: Filtering was performed after deserialization. However, the built-in RTI SQL filter expects samples in the Connext memory layout. Because ROS 2 uses its own internal format, the filter would fail "open" and accept all samples.

This led to failures in rcl, rclcpp, and rcl_action tests where samples were received by subscribers despite being explicitly filtered out by SQL expressions.

The Fix

1. Enable Serialized Evaluation: Updated CMakeLists.txt to only enable RMW_CONNEXT_BUILTIN_CFT_COMPATIBILITY_MODE on Windows for Connext versions older than 6.0.0. For modern versions, we now use the internal register_contentfilterI API, which supports evaluation on CDR-serialized samples.
2. Fix Redefinition Conflict: Adjusted custom_sql_filter.hpp to use the official RTI declaration of register_contentfilterI (available in modern headers) to avoid linkage errors on MSVC.
3. Correct Cookie Handling: Fixed a bug in RTI_CustomSqlFilter_writer_evaluated_result where it assumed RTI's built-in filter always returned a discontiguous sequence of cookies. It now correctly handles both contiguous and discontiguous sequences.

Verification

Verified on Windows using a targeted CI run with Connext 7.7.0. All content filtering tests in rcl, rclcpp, and rcl_action passed.

CI Result (Windows 10, Connext 7.7.0): https://ci.ros2.org/job/ci_windows/27743/

Is this user-facing behavior change?

No, it fixes a regression in existing functionality.

Did you use Generative AI?

Yes. Gemini CLI:2.0-Flash [web_fetch, run_shell_command, replace, git, gh]

---

This is an automatic backport of pull request #226 done by [Mergify](https://mergify.com).

[sloretz]

CI (build: --packages-up-to rcl rcl_action rclpy ros2cli sros2 ros2multicast test_rmw_implementation rclcpp rosbag2_transport test_communication test_tf2 test_security rmw_connextdds_common test: --packages-select rcl rcl_action rclpy ros2cli sros2 ros2multicast test_rmw_implementation rclcpp rosbag2_transport test_communication test_tf2 test_security rmw_connextdds_common)

• Linux
• Linux-aarch64 (Expected failure; CI ignores ConnextDDS on aarch64)
• Linux-rhel
• Windows

[sloretz]

I think Windows CI is ok. The only test failure in window CI not in the nightly is rosbag2_transport.test_record_services.gtest.missing_result. It's weird because I'm using the Lyrical repos instead of the rolling repos, but Clara did say today the test failures are new due to an infra issue.