Add enable_millisecond to duration selector (#122821)

* Add enable_milliseconds to duration selector.

* One more test

homeassistant/helpers/selector.py

@@ -725,6 +725,7 @@ class DurationSelectorConfig(TypedDict, total=False):
     """Class to represent a duration selector config."""
 
     enable_day: bool
+    enable_millisecond: bool
     allow_negative: bool
 
 
@@ -739,6 +740,8 @@ class DurationSelector(Selector[DurationSelectorConfig]):
             # Enable day field in frontend. A selection with `days` set is allowed
             # even if `enable_day` is not set
             vol.Optional("enable_day"): cv.boolean,
+            # Enable millisecond field in frontend.
+            vol.Optional("enable_millisecond"): cv.boolean,
             # Allow negative durations. Will default to False in HA Core 2025.6.0.
             vol.Optional("allow_negative"): cv.boolean,
         }