Remove fractions for percentages in tracing

(59.00%) -> (59%)

[Mindy / Polina (2022-10-21 11:39 GMT-7)](http://go/mindy-polina-2022-10-21-11:39-gmt-7), at 22:30

decimals in percentages may not be necessary if the number of instances is provided. If there are a very large number of instances, a more detailed percentage might be nice, but not necessary. It isn't cluttering the interface too much, so it isn't a high priority to me. -Mindy

定位用于格式化百分比值的 tracing UI 代码，并检查相关的显示路径。当 59.00% 这样的百分比显示为 59%，同时仍可获得关联的实例数量时，此更改即完成；issue 中未指定文件或测试。

由索引模型根据 Issue 内容生成。