fix(tests): Revert default to previous formatter.

* new cbprintf formatter causes issues for our use of string formatting.

See: https://github.com/zephyrproject-rtos/zephyr/pull/29876
PR: https://github.com/zmkfirmware/zmk/pull/736

app/Kconfig

@@ -419,6 +419,11 @@ config ZMK_WPM
 config SENSOR
 	default y
 
+choice CBPRINTF_IMPLEMENTATION
+	default CBPRINTF_NANO
+
+endchoice
+
 module = ZMK
 module-str = zmk
 source "subsys/logging/Kconfig.template.log_config"