[snapshot] fix compiler error on SnapshotHelper.swift (#20689)

* SnapshotHelper.swift has Swift Compiler Error #18792

* Updated snapshot helper version

Co-authored-by: Josh Holtz <me@joshholtz.com>

snapshot/lib/assets/SnapshotHelper.swift

@@ -181,7 +181,7 @@ open class Snapshot: NSObject {
 
                 let path = screenshotsDir.appendingPathComponent("\(simulator)-\(name).png")
                 #if swift(<5.0)
-                    UIImagePNGRepresentation(image)?.write(to: path, options: .atomic)
+                    try UIImagePNGRepresentation(image)?.write(to: path, options: .atomic)
                 #else
                     try image.pngData()?.write(to: path, options: .atomic)
                 #endif
@@ -306,4 +306,4 @@ private extension CGFloat {
 
 // Please don't remove the lines below
 // They are used to detect outdated configuration files
-// SnapshotHelperVersion [1.28]
+// SnapshotHelperVersion [1.29]