ux: Mute selected text

This PR adds the Mute action to the selected text menu. Pressing the mute
action will pop up a sheet which allows users to confirm their selection and
choose for how long they would like to mute the selected text for.

Changelog-Added: Added mute action to selected text menu

Signed-off-by: ericholguin <ericholguin@apache.org>

damus/Views/Muting/AddMuteItemView.swift

@@ -8,7 +8,7 @@ import SwiftUI
 
 struct AddMuteItemView: View {
     let state: DamusState
-    @State var new_text: String = ""
+    @Binding var new_text: String
     @State var expiration: DamusDuration = .indefinite
 
     @Environment(\.dismiss) var dismiss
@@ -108,6 +108,6 @@ struct AddMuteItemView: View {
 
 struct AddMuteItemView_Previews: PreviewProvider {
     static var previews: some View {
-        AddMuteItemView(state: test_damus_state)
+        AddMuteItemView(state: test_damus_state, new_text: .constant(""))
     }
 }