Feature Request : Consider making the ImageOptions properties such as N, Quality, dimensions etc to be an enum

[Shandilya]

Consider making the ImageOptions properties such as N, Quality, dimensions etc to be an enum. For example, OpenAiImageOptions quality could be of two types, standard & hd. So if the well known property values are made as enum, it would help the devs and avoid them making wrong calls. For example, I was not aware of the standard type, so having seen hd, I supplied sd, thinking standard definition i.e. sd, would be supported, however this wasn't the case and I lost a few tokens in this call. Likewise, I lost quite a few iterations for the dimensions as well. With this kind of use case, please do consider making these kind of properties to be enum while retaining the current string type support (this will help with future extensibility, where a new feature introduced by any LLM could be supplied as String till the time the enum isn't updated). Thanks!