NIU Actions: Update text color in dialogs

textColorSecondary was deemed too similar to the dialog headers, so we're switching to textColorTertiary instead.

Bug: 194458828
Test: Manual (looked at updated dialogs on Wembley)
Change-Id: I2e4f5c48da35ca21d01c25e279ff9c2f6b5a5107
diff --git a/go/quickstep/res/values/styles.xml b/go/quickstep/res/values/styles.xml
index 442c413..c659331 100644
--- a/go/quickstep/res/values/styles.xml
+++ b/go/quickstep/res/values/styles.xml
@@ -73,7 +73,7 @@
     <style name="ModalDialogText">
         <item name="android:fontFamily">sans-serif-medium</item>
         <item name="android:textSize">16sp</item>
-        <item name="android:textColor">?android:attr/textColorSecondary</item>
+        <item name="android:textColor">?android:attr/textColorTertiary</item>
         <item name="android:lineHeight">24dp</item>
         <item name="android:layout_width">match_parent</item>
         <item name="android:layout_height">wrap_content</item>