Revert "Make CharacterPickerDialog use holo theme"

This reverts commit fad769c5566d08fa07727a8e48b4433beb3a55d4.
Make character picker for QWERTY keyboards use HOLO theme

Also, removed the cancel button. Instead, touching outside will close
the dialog.

Change-Id: Ie910bff67fb02f9c07e2d1f3f26b345d03e4883c