fix: RNFS.touch fails if mtime or ctime are not set

Author: mnightingale

src/FileSystem.tsx

@@ -258,7 +258,7 @@ export class FileSystem {
       await (move ? RNFS.moveFile(local, path) : RNFS.copyFile(local, path))
 
       // Update the modified and created times of the file otherwise the if-modified-since request will probably always
-      await RNFS.touch(path, mtime, ctime)
+      await RNFS.touch(path, mtime ?? new Date(), ctime ?? new Date())
     } catch (error) {
       await RNFSUnlinkIfExists(path)
       return {