ci: Enable esp32c6 example, test_apps, and unit tests CI build stage

examples/peripherals/pcnt/rotary_encoder/pytest_rotary_encoder.py

@@ -8,6 +8,7 @@ from pytest_embedded.dut import Dut
 @pytest.mark.esp32
 @pytest.mark.esp32s2
 @pytest.mark.esp32s3
+@pytest.mark.esp32c6
 @pytest.mark.generic
 def test_rotary_encoder(dut: Dut) -> None:
     dut.expect_exact('install pcnt unit')