match new placeholder avatar with Android

SignalMessaging/Loki/Redesign/Components/Identicon+ObjC.swift

@@ -4,7 +4,11 @@ public final class Identicon : NSObject {
     
     @objc public static func generatePlaceholderIcon(seed: String, text: String, size: CGFloat) -> UIImage {
         let icon = PlaceholderIcon(seed: seed)
-        let layer = icon.generateLayer(with: size, text: text.substring(to: 1))
+        var content = text
+        if content.count > 2 && content.hasPrefix("05") {
+            content.removeFirst(2)
+        }
+        let layer = icon.generateLayer(with: size, text: content.substring(to: 1))
         let rect = CGRect(origin: CGPoint.zero, size: layer.frame.size)
         let renderer = UIGraphicsImageRenderer(size: rect.size)
         return renderer.image { layer.render(in: $0.cgContext) }

SignalMessaging/Loki/Redesign/Components/PlaceholderIcon.swift

@@ -18,7 +18,7 @@ public class PlaceholderIcon {
     convenience init(seed: String, colours: [UIColor]? = nil) {
         // Ensure we have a correct hash
         var hash = seed
-        if !hash.matches("^[0-9A-Fa-f]+$") || hash.count < 12 { hash = seed.sha512() }
+        if (hash.matches("^[0-9A-Fa-f]+$") && hash.count >= 12) { hash = seed.sha512() }
         
         guard let number = Int(hash.substring(to: 12), radix: 16) else {
             owsFailDebug("Failed to generate number from seed string: \(seed).")