Layout and style updates for LongScreenshotActivity

- Give save button accent color.
- Remove cancel button (may come back in another form later)
- Share button becomes and icon on the right.
- Edit button moves to the bottom, gets icon + text

Bug: 180967468
Test: Visual eval with light and dark themes
Change-Id: I19ccea06e7dbec47b26ffd0684ebb7e31bdfe8b4
diff --git a/packages/SystemUI/AndroidManifest.xml b/packages/SystemUI/AndroidManifest.xml
index 338aa3a..3904201 100644
--- a/packages/SystemUI/AndroidManifest.xml
+++ b/packages/SystemUI/AndroidManifest.xml
@@ -336,7 +336,7 @@
         </receiver>
 
         <activity android:name=".screenshot.LongScreenshotActivity"
-                  android:theme="@android:style/Theme.DeviceDefault.NoActionBar"
+                  android:theme="@style/LongScreenshotActivity"
                   android:process=":screenshot"
                   android:exported="false"
                   android:finishOnTaskLaunch="true" />