Update modal download dialogs for sdk/ndk download. Revise the redirect...

Update modal download dialogs for sdk/ndk download. Revise the redirect behavior once download completes. Add more appropriate title and download message when installing SDK tools only. Force refresh when the Studio download dialog is dismissed, to avoid leaving the dialog in stale state. Add styles for the Studio download page. am: c607a4d4 am: 29e355b2
am: b969b158

* commit 'b969b158':

Change-Id: Ic7e066ec008b7b8bdae4a016acaf91d38a324ed7