Fix typos (#15445)

FirebaseAI/Sources/Types/Internal/Live/LiveSessionService.swift

@@ -105,7 +105,7 @@ actor LiveSessionService {
 
   /// Start a new connection to the backend.
   ///
-  /// Seperated into its own function to make it easier to surface a way to call it seperately when
+  /// Separated into its own function to make it easier to surface a way to call it separately when
   /// resuming the same session.
   ///
   /// This function will yield until the websocket is ready to communicate with the client.

FirebaseAI/Sources/Types/Public/Live/LiveSession.swift

@@ -72,7 +72,7 @@ public final class LiveSession: Sendable {
   /// Instead of raw video data, the model expects individual frames of the video,
   /// sent as images.
   ///
-  /// If your video has audio, send it seperately through ``LiveSession/sendAudioRealtime(_:)``.
+  /// If your video has audio, send it separately through ``LiveSession/sendAudioRealtime(_:)``.
   ///
   /// For better performance, frames can also be sent at a lower rate than the video;
   /// even as low as 1 frame per second.

FirebaseAI/Tests/TestApp/Tests/Integration/LiveSessionTests.swift

@@ -484,7 +484,7 @@ private extension LiveSession {
   /// }
   /// ```
   ///
-  /// Is the equivelent to manually doing:
+  /// Is the equivalent to manually doing:
   /// ```swift
   /// for try await response in session.responses {
   ///   if case let .content(content) = response.payload {