feat(datetime): add ionic theme styles to time label (#29829)

Issue number: internal
---------

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## What is the current behavior?
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No `ionic` theme styles for the datetime time label

## What is the new behavior?
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this PR. -->

Adds styles to the time label for the `ionic` theme

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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## Other information

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screenshots of how the component looks before and after the change. -->


[Preview](https://ionic-framework-6m937m00k-ionic1.vercel.app/src/components/datetime/test/basic?ionic:theme=ionic)

core/src/components/datetime/datetime.ionic.scss

@@ -173,3 +173,30 @@
 .calendar-day:active {
   background: globals.$ionic-color-primary-300;
 }
+
+// Time / Header
+// -----------------------------------
+:host .datetime-time {
+  @include globals.padding(globals.$ionic-space-100, globals.$ionic-space-400);
+
+  height: globals.$ionic-scale-800;
+}
+
+:host .datetime-time .time-header {
+  @include globals.typography(globals.$ionic-action-lg);
+
+  color: globals.$ionic-color-neutral-800;
+}
+
+:host .datetime-time button {
+  @include globals.padding(globals.$ionic-space-0, globals.$ionic-space-200);
+  @include globals.typography(globals.$ionic-body-md-medium);
+  @include globals.border-radius(globals.$ionic-border-radius-full);
+
+  display: flex;
+
+  align-items: center;
+
+  background-color: globals.$ionic-color-neutral-100;
+  color: globals.$ionic-color-neutral-1200;
+}