CarrierDefaultApp: Add an exported flag in manifest

With b/150232615, we will need an explicit value set for the exported
flag when intent filters are present, as the default behavior is
changing for S+. This change adds the value reflecting the previous
default to the manifest.

Bug: 150232615
Test: TH
Change-Id: I03108f520f7e04a5ddb9c43c2075591bd6c45fdf
1 file changed