Compound - Swift 6.2 and Main actor isolation (#5109)

* compound is now using 6.2 and main actor isolation + some tweaks to make it build tests and EX

* better handling of the nonisolated context for CompoundUIColors

* improving docs

* fix comment

* remove unused Sendable conformance

ElementX/Sources/Screens/RoomScreen/RoomScreenModels.swift

@@ -109,6 +109,7 @@ enum RoomScreenFooterViewDetails {
     case verificationViolation(member: RoomMemberProxyProtocol, learnMoreURL: URL)
 }
 
+@MainActor
 enum PinnedEventsBannerState: Equatable {
     case loading(numbersOfEvents: Int)
     case loaded(state: PinnedEventsState)
@@ -213,6 +214,7 @@ enum PinnedEventsBannerState: Equatable {
     }
 }
 
+@MainActor
 struct PinnedEventsState: Equatable {
     var pinnedEventContents: OrderedDictionary<String, AttributedString> = [:] {
         didSet {