switch to previous backend when leaving PiP

Currently, when leaving PiP the backend doesn't switch to the one that was used before starting PiP.

Now, when the backend was MPV, it switches back to it after leaving PiP.

Model/Player/PlayerModel.swift

@@ -76,6 +76,8 @@ final class PlayerModel: ObservableObject {
         }
     }
 
+    var previousActiveBackend: PlayerBackendType?
+
     lazy var playerBackendView = PlayerBackendView()
 
     @Published var playerSize: CGSize = .zero { didSet {
@@ -532,7 +534,7 @@ final class PlayerModel: ObservableObject {
         }
     }
 
-    func changeActiveBackend(from: PlayerBackendType, to: PlayerBackendType, changingStream: Bool = true) {
+    func changeActiveBackend(from: PlayerBackendType, to: PlayerBackendType, changingStream: Bool = true, isInClosePip: Bool = false) {
         guard activeBackend != to else {
             return
         }
@@ -541,7 +543,7 @@ final class PlayerModel: ObservableObject {
 
         let wasPlaying = isPlaying
 
-        if to == .mpv {
+        if to == .mpv && !isInClosePip {
             closePiP()
         }
 
@@ -664,6 +666,7 @@ final class PlayerModel: ObservableObject {
     }
 
     func startPiP() {
+        previousActiveBackend = activeBackend
         avPlayerBackend.startPictureInPictureOnPlay = false
         avPlayerBackend.startPictureInPictureOnSwitch = false
 
@@ -716,6 +719,12 @@ final class PlayerModel: ObservableObject {
         #endif
 
         backend.closePiP()
+        if previousActiveBackend == .mpv {
+            saveTime {
+                self.changeActiveBackend(from: self.activeBackend, to: .mpv, isInClosePip: true)
+                self.controls.resetTimer()
+            }
+        }
     }
 
     var pipImage: String {