test(lp_core): use soc_filtered_targets for all LP core pytest parametrization

Several LP core pytest files were either hardcoded to specific chip lists
or using a less-precise SOC capability filter:

- test_lp_core_multi_device: was locked to ['esp32c6'] pending a workaround
  for LP I2C on esp32p4; all three active LP core chips now have
  SOC_LP_I2C_SUPPORTED=1, so switch to soc_filtered_targets.

- test_lp_uart_wakeup_modes: was using SOC_LP_CORE_SUPPORTED which is
  semantically wrong for a UART test; change to SOC_ULP_LP_UART_SUPPORTED.

- LP core example pytests (build_system, interrupt, gpio_intr_pulse_counter,
  lp_timer_interrupt): replace hardcoded ['esp32c5', 'esp32c6', 'esp32p4']
  with soc_filtered_targets('SOC_LP_CORE_SUPPORTED == 1') so that new
  chips automatically get coverage when their SOC cap is enabled.

components/ulp/test_apps/lp_core/lp_core_basic_tests/pytest_lp_core_basic.py

@@ -46,7 +46,6 @@ def test_lp_vad(dut: Dut) -> None:
     dut.run_all_single_board_cases(group='lp_vad')
 
 
-# TODO: Support LP I2C test for esp32p4 (IDF-9581)
 @pytest.mark.generic_multi_device
 @pytest.mark.parametrize('count', [2], indirect=True)
 @pytest.mark.parametrize(
@@ -56,7 +55,7 @@ def test_lp_vad(dut: Dut) -> None:
     ],
     indirect=True,
 )
-@idf_parametrize('target', ['esp32c6'], indirect=['target'])
+@idf_parametrize('target', soc_filtered_targets('SOC_LP_I2C_SUPPORTED == 1'), indirect=['target'])
 def test_lp_core_multi_device(case_tester: CaseTester) -> None:
     # Run only non-UART multi-device cases (e.g. LP I2C); LP UART is covered
     # by test_lp_uart_multi_device which targets all LP_CORE_SUPPORTED chips.
@@ -84,11 +83,7 @@ def test_lp_uart_multi_device(case_tester: CaseTester) -> None:
 @pytest.mark.generic_multi_device
 @pytest.mark.parametrize(
     'target',
-    [
-        'esp32c5',
-        'esp32c6',
-        'esp32p4',
-    ],
+    soc_filtered_targets('SOC_ULP_LP_UART_SUPPORTED == 1'),
     indirect=True,
 )
 @pytest.mark.parametrize(