Add missing hyphen to "mains-powered" and "battery-powered" in zha (home-assistant#147128)

Add missing hyphen to "mains-powered" and "battery-powered"

Author: NoRi2909

homeassistant/components/zha/strings.json

@@ -182,9 +182,9 @@
       "group_members_assume_state": "Group members assume state of group",
       "enable_identify_on_join": "Enable identify effect when devices join the network",
       "default_light_transition": "Default light transition time (seconds)",
-      "consider_unavailable_mains": "Consider mains powered devices unavailable after (seconds)",
-      "enable_mains_startup_polling": "Refresh state for mains powered devices on startup",
-      "consider_unavailable_battery": "Consider battery powered devices unavailable after (seconds)"
+      "consider_unavailable_mains": "Consider mains-powered devices unavailable after (seconds)",
+      "enable_mains_startup_polling": "Refresh state for mains-powered devices on startup",
+      "consider_unavailable_battery": "Consider battery-powered devices unavailable after (seconds)"
     },
     "zha_alarm_options": {
       "title": "Alarm control panel options",