fix: Provide In-Editor Relay Connection Testing Capabilities [MTT-7718] (#2740)

* feat: extra API StartHostWithRelay

* Refactoring: extracted functions in OnInspectorGUI of network manager

* feat: modified inspector buttons to use relay

* feat: added button to copy join code in inspector

* feat: show warning if project id not setup in project settings

* fix: checked if signed in before trying again

* feat: support WebGL

* feat: force using Unity transport

* fix: make transport.UseWebSockets match connection type

IMO it would be nicer in SetRelayServerData

* feat: added StartServer button

* feat: modified api to return allocation data and show region in inspector

* feat: added doc button

* fix: UseWebSockets for UTP 2.0 only

* fix: relay integration false by default

* fix: clear join code when stopping host/server/client

otherwise the UI shows the wrong thing if you stop then start a host that does not use relay

* fix: let imgui finish current frame and repaint after async call

* cosmetic fix: input field forced at 50%

* fix: 2021.3 support

* style

Fixing whitespace issues.

* style

Fixing some white space issues hidden by defines.

* style

Last missed whitespace issue and possible return missing.

* update - needs fixing

Ran across an issue with how the connection type is being set.
The connection type should be (most likely) an enum and exposed as a property in UX/UI inspector view.

* style

fixing minor style issue during construction to simplify the assignments.

* style

arrrg...dang whitespace issues are doing a "whack-a-mole"... :)

* style

Fun with defines!
Evidently, a CREF that uses the full namespace path when a portion of that path is being used by the csharp file will cause a validation error...

* design: move join code field down and added label

* fix: error handling in the inspector (HelpBox)

* design: implemented feedback for join code button box

* feat!: no support of relay integration for 2021.3

After discussion with product.
This reverts f2e0463

* cosmetic: capitalisation of "Editor"

* feat: to validate: expose conn type

* doc: missing exception in xml doc

* refactor: move everything to the editor assembly

as discussed with Erick Boulay

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Co-authored-by: NoelStephensUnity <[email protected]>

Author: TiphaineRousseauU