* Revert "Do not register UI-related native functions in secondary isolates (#6401)"
This reverts commit 69ae5694de54d2a163743dcec727fcea1c7bc8e1 as it doesn't work when root and secondary isolates run in the same isolate group.
* Confirm it is root isolate that makes UI native calls.
* Fix format, UIDartState reference from Fuchsia source
* No UI isolate check for fuchsia calls
* Fix typo. Remove redundant runtime calls