Misc app mode fixes (#9368)

A working branch of smaller app mode fixes. Can be merged at any time
and I'll make a new branch.
- Selected inputs and outputs can now be re-ordered when clicking on
label text
- 3d outputs once again display correctly
- Some padding has been added to the side so that control buttons don't
overlap with the floating app sidebar controls
- A "Share" button placeholder has been added to the menu, but is
disabled
- Adds a workaround for canvas read_only state being disabled when
'space' is pressed.
  - This one is particularly hacky, and can be pulled out if problematic
- Fix download all only downloading the first output

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9368-Misc-app-mode-fixes-3196d73d365081eab02ad1e693784707)
by [Unito](https://www.unito.io)

packages/design-system/src/icons/send.svg

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