Fix dark navigationBar background in some telephony settings pages

Style changes:

- Organize styles.xml, make Theme.Telecom.DialerSettings as a base settings theme, and declare navigationBarColor transparent.

- Align EnableAccount\BlockedNumbers\CallSettingsWithoutDividerTheme extending this base settings theme.

Affected pages:
EnableAccountPreferenceActivity\RespondViaSmsSettings\BlockedNumbersActivity

Bug: b/253168764 b/236809093
Test: Manual UI test in normal and dark mode

Change-Id: Iced178b2edfeb5a6f8d2bb6048b353e38981fb97
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index d376b6a..b43be0f 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -276,7 +276,7 @@
         <activity android:name=".settings.EnableAccountPreferenceActivity"
              android:label="@string/enable_account_preference_title"
              android:configChanges="orientation|screenSize|keyboardHidden"
-             android:theme="@style/Theme.Telecom.DialerSettings"
+             android:theme="@style/Theme.Telecom.EnableAccount"
              android:process=":ui"
              android:exported="true">
             <intent-filter>