Add schedule setting page for time-based modes.

Creates new layout for setting the start & end time, and days of the week, for a schedule-based mode.

This is close to the mocks specified in https://screenshot.googleplex.com/8zmb7PAjjt73VkN, but with the following differences:
- the end time is left-aligned with the center rather than on the right side of the screen. This is a side effect of using LinearLayout to evenly space start & end times, and could in theory be fixed by using a ConstraintLayout, but that option seems to cause times to overlap instead of wrap when display size is cranked up. Could be fixed later.
- no icons yet on either side of the time display
- no Done button. Instead, has the "exit at alarm" switch that exists today.

Have not yet checked how this interacts with TalkBack, etc.

Flag: android.app.modes_ui
Bug: 332730302
Test: ZenModeSetSchedulePreferenceControllerTest, ZenModeExitAtAlarmPreferenceControllerTest, ZenModeSetTriggerLinkPreferenceControllerTest
Test: manual: interacting with UI in normal size, with font & display at minimum and maximum, and in locales (fr) where the first day of the week is a different day
Change-Id: I0b76f55891d6c12fc27720657c9eea6fe42fbafe

res/color/modes_set_schedule_text_color.xml

@@ -0,0 +1,27 @@
+<!--
+  ~ Copyright (C) 2024 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<selector
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- when checked, background color will be accent color -->
+    <item
+        android:state_checked="true"
+        android:color="?android:attr/textColorPrimaryInverse" />
+    <!-- when unchecked, background color will be transparent -->
+    <item
+        android:state_checked="false"
+        android:color="?android:attr/colorAccent" />
+</selector>