Implement frequency tracking for frequently used emojis

ElementX/Sources/Services/Emojis/EmojiProviderProtocol.swift

@@ -31,6 +31,15 @@ enum EmojiProviderState {
     case loaded([EmojiCategory])
 }
 
+struct FrequentlyUsedEmoji: Codable, Hashable {
+    let count: UInt
+    let key: String
+    
+    static func == (lhs: FrequentlyUsedEmoji, rhs: FrequentlyUsedEmoji) -> Bool {
+        lhs.key == rhs.key
+    }
+}
+
 @MainActor
 protocol EmojiProviderProtocol {
     var state: EmojiProviderState { get }