Move the linkItem dialog to the top

Having it horizontally centered might make it overflow
in the second step (where the dialog gets larger).

Bug: 72687
Change-Id: I4b1be1f6c5ace22f46081ce487e69155306c56f0
Allow submitting linkItem form with enter

And be smarter about enabling/ disabling the submit button.

Bug: 72712
Change-Id: Ib3e9ebf1d58874fed127ba6830f76b441e21cb8e
Merge "Allow submitting linkItem form with enter"
Merge "Move the linkItem dialog to the top"