All keys in UploadAPIResponse should be optional

[ahnv]

Since there is a feature to get only the required fields in the UploadAPI, if one of the required field is not passed in responseFields parameter, it will throw an encoding error

imagekit-ios/ImageKit/Entity/UploadAPIResponse.swift

Lines 12 to 17 in fd12f3e

	public let fileId, name, url, filePath, fileType: String
	public let height, width: Int?
	public let size: Int
	public let tags: [String]?
	public let isPrivateFile: Bool?
	public let customCoordinates, metadata, thumbnailUrl: String?

[ahnv]

Fixed