fix(clr/shared): fix GetGamePool for server

[AvarianKnight]

Goal of this PR

Fix bug for mono_rt2 server implementation introduced in https://github.com/citizenfx/fivem/pull/2488 (and temp fixed in https://github.com/citizenfx/fivem/commit/3768dc04fa2d53030f0d52b362340c2b7ed2131b)

This also changes the server variant for mono_rt2 from Object -> Prop fixing an oversight in https://github.com/citizenfx/fivem/pull/2731

This relies on on other changes so this will be marked as a draft for now.

How is this PR achieving the goal

Properly use server namespaces for native invokes

This PR applies to the following area(s)

Server

Successfully tested on

Game builds: ..

Platforms: Windows, Linux

Checklist

• [ ] Code compiles and has been tested successfully.
• [x] Code explains itself well and/or is documented.
• [x] My commit message explains what the changes do and what they are for.
• [x] No extra compilation warnings are added by these changes.

Fixes issues

[AvarianKnight]

This relies on https://github.com/citizenfx/fivem/pull/2739 to work

[mcNuggets1]

At this point if not already happened, they should hire you.