Z2M: fix action expose (e.presets.action, not e.action)

The action expose was written as `e.action(...)`, but zigbee-herdsman-converters
exposes `action` only under `presets` — there is no top-level `e.action`. Z2M
rejected the whole converter at load with "e.action is not a function" and
renamed the file, dropping every custom device back to an auto-generated
definition. (This is the multistate proposal's own bug: its committed converter
was never regenerated, so the call was never exercised.)

Verified by loading the generated converter against zigbee-herdsman-converters
26.85.0: 147 definitions build cleanly.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: neneonline

helper_scripts/templates/switch_custom.js.jinja

@@ -535,7 +535,7 @@ const definitions = [
                     },
                 }],
                 toZigbee: [],
-                exposes: [e.action({{ action_values | tojson }})],
+                exposes: [e.presets.action({{ action_values | tojson }})],
             },
             {% endif %}
             {% for switchName in device.switchNames %}