Increase max shortcut limit to 10

Increase the maximum allowed shortcuts per activity from 5 to 10, to
accommodate the extra sharing shortcuts.

Bug: 123899560
Test: atest com.android.server.pm.ShortcutManagerTest1
Test: atest com.android.server.pm.ShortcutManagerTest2
Test: atest com.android.server.pm.ShortcutManagerTest3
Test: atest com.android.server.pm.ShortcutManagerTest4
Test: atest com.android.server.pm.ShortcutManagerTest5
Test: atest com.android.server.pm.ShortcutManagerTest6
Test: atest com.android.server.pm.ShortcutManagerTest7
Test: atest com.android.server.pm.ShortcutManagerTest8
Test: atest com.android.server.pm.ShortcutManagerTest9
Test: atest com.android.server.pm.ShortcutManagerTest10
Test: atest CtsShortcutHostTestCases
Test: atest CtsShortcutManagerTestCases

Change-Id: I9584b6b5a43e3d35eea304e820d6cff091b70441