#36033)

* Start moving user agent utils into shared package

* Remove inobounce and stop exporting isIosSafari

Based on some quick testing on my phone, inobounce is no longer needed. Both
local and Community:
1. Let you overscroll on the landing and login pages
2. Don't overscroll in a channel, a thread, or the LHS while fully zoomed out
3. Do let you overscroll when zoomed in

That also lets me reduce the size of the interface for utils/user_agent.

* Remove unneeded exports and unused functions

* Remove outdated workarounds from FileUpload component

These were only needed to support a 10 year old version of iOS Chrome and the classic app.

* Remove useOrientationHandler

This was added in mattermost/mattermost-webapp#2504,
but I don't think the extra complexity is worth keeping it around
when we mostly support mobile view for desktop accessibility reasons.

* Replace isIosWeb/isAndroidWeb with isIos/isAndroid

These were previously needed to differentiate between the mobile web app
and the classic app.

* Replace isMobileApp with isMobile

Similar to the last commit, we used to need to differentiate
between the mobile web and the classic app. For most places,
I just replaced isMobileApp with isMobile, but I removed the
check in ProductMenuList because we want to show that link
on mobile web.

* Move isInternetExplorer and isEdge out of the shared package

Those should be removed, so I don't want to include them in
the shared package at all. I also renamed isChromiumEdge to
just isEdge since that should be its name once the old ones
are removed.

* Change how functions are re-exported to fix tests

* Update web app code to use shared user agent utils directly

* Removed useless mock

* Fix how tests mock utils/user_agent now that it's fully moved

* Actually export user_agent utils from shared package