optimize: remove the limit of total weight in weighted cluster

[ppzqh]

What type of PR is this?

optimize

What this PR does / why we need it (en: English/zh: Chinese):

zh: optimize: 去除 weighted cluster 的总权重限制

Which issue(s) this PR fixes:

[bytedance-oss-robot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ppzqh

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/kitex-contrib/xds/blob/main/OWNERS)~~ [ppzqh] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[whalecold]

LGTM