Force share intents to use Strings instead of SpannableString

Fix: 238837981
Test: copy text, go to edit, recopy, click share, attempt to copy
(this is a simple way of getting a SpannableString, since the
text from the editor is underlined)
atest IntentCreatorTest

Change-Id: Ice6c22a53abf149befa9065f478e45d161dfb5bd