Move the mojom & typemap for ui::TextInputType to ui/base/ime/mojo.

Currently the mojom for ui::TextInputType is under ui/platform_window/mojo,
and the typemap is under services/ws/public/mojom/ime.
It will cause problem if some other code wants to use ui.mojom.TextInputType.

ui::TextInputType is defined under ui/base/ime, where the mojom and typemap should be.

Bug: 937167
Change-Id: Ie62a49e7d9f0be5d8f6b9038b581543b8d9ca0c5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1517339
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Shu Chen <shuchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641049}