Remove `secure_wan` test from the list of failing tests

[tempate]

The PR https://github.com/eProsima/Fast-DDS/pull/5071 fixes a known issue in Fast-DDS's security over WAN. This issue made the secure_wan test fail, forcing us to place it in the list of failing tests (TEST_XFAIL). Since the test should now pass, we will remove it from the list of failing tests.

Merge after:

• https://github.com/eProsima/Fast-DDS/pull/5071
• https://github.com/eProsima/DDS-Router/pull/418