[nrf52] Use full newlib when the logger is enabled, disable unused serial and printk (#19766)

Co-authored-by: J. Nick Koston <nick@home-assistant.io>

tests/components/logger/test.nrf52-mcumgr.yaml

@@ -5,3 +5,4 @@ esphome:
 
 logger:
   level: DEBUG
+  hardware_uart: UART0

tests/unit_tests/test_nrf52_config.py

@@ -0,0 +1,12 @@
+"""Tests for the nRF52 configuration validation."""
+
+import pytest
+
+from esphome.components.nrf52 import _detect_bootloader
+import esphome.config_validation as cv
+
+
+def test_detect_bootloader_reports_a_missing_board() -> None:
+    """The bootloader check runs before the schema, so it reports the missing key."""
+    with pytest.raises(cv.Invalid, match="'board' is a required option"):
+        _detect_bootloader({})