For ListFileshares API, no need to seperate listFileShareByBackend and listFileShareDefault.

[sfzeng]

Issue/Feature Description: As per my understanding, we can use one function to handle ListFileshares, just update suported filters, that can make our code be simple and clean.

Why this issue to fixed / feature is needed(give scenarios or use cases):

How to reproduce, in case of a bug:

Other Notes / Environment Information: (Please give the env information, log link or any useful information for this issue)