Testing: split input test (#2762)

test(pointing): Add mock input device.

New mock input device to generate input events for tests.

test(split): Add peripheral input test.

Test event propagation from peripheral input devices.

fix(split): Proper scoping for local within switch.

Minor compile fix.

chore: Fix up test snapshots after logging changes.

Adjust the test snapshots after logging changes to the central.

fix(kscan): Don't fire last mock event twice.

Fix a bug where the kscan mock would raise the last mock event
twice before halting processing.

app/module/drivers/input/Kconfig

@@ -0,0 +1,9 @@
+
+if INPUT
+
+config ZMK_INPUT_MOCK
+    bool "Input Mock"
+    default y
+    depends on DT_HAS_ZMK_INPUT_MOCK_ENABLED
+
+endif