[iOS] Add FileUploadPanelCommands

This CL adds FileUploadPanelCommands and registers BrowserCoordinator as
handler for these commands. ChooseFileTabHelper::RunOpenPanel() is given
the handler as dependency and calls -showFileUploadPanel when
RunOpenPanel() is called.

Bug: 441659098
Change-Id: I263ca51bf9c056b8900b248e0e2cab8db250f69f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7002915
Commit-Queue: Quentin Pubert <qpubert@google.com>
Auto-Submit: Quentin Pubert <qpubert@google.com>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1525535}