AT2 CI Build Transition -- clang

[achauphan]

The current AutoTester2 clang19-openmpi4 GitHub Action will be set to be required on Monday 09-29-2025.

Since its addition on 08-12-2025 (#14307), it has had a high enough success rate to warrant this transition (CDash history).

Along with this transition, will be the removal of the existing AutoTester1 clang-11.0.1-openmpi-4.0.5 CI build also on Monday 09-29-2025.

If you encounter any issues that you think are related to this change, please open an issue and tag @trilinos/framework.

[achauphan]

clang19-openmpi4 AT2 job has now been set to required for develop and master branches.

[achauphan]

The AutoTester1 job, rhel8_sems-clang-11.0.1-openmpi-4.0.5-serial_release-debug_shared_no-kokkos-arch_no-asan_no-complex_no-fpic_mpi_no-pt_no-rdc_no-uvm_deprecated-on_no-package-enables, has been removed.

This transition is now complete.