fix(tests): Revert default to previous formatter.

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

See: zephyrproject-rtos/zephyr#29876

Author: petejohanson

Diff for: 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"