[Bug Report] el-tabs__active-bar width calculation is incorrect

[weeqe]

Element UI version

2.7.2

OS/Browsers version

win10,chrome 72.0.3626.121

Vue version

2.5.16

Reproduction Link

https://codepen.io/anon/pen/axaodL?&editable=true

Steps to reproduce

定时补偿任务的子菜单el-tabs__active-bar宽度计算不正确，且只有el-tabs的type为border-card或card的时候才会出现

What is Expected?

修改el-tabs__active-bar宽度

What is actually happening?

宽度不一致

[element-bot]

Translation of this issue:

Element UI version

2.7.2

OS/Browsers version

Win10, chrome 72.0.3626.121

Vue version

2.5.16

Reproduction Link

Https://codepen.io/anon/pen/axaodL?&editable=true

Steps to reproduce

The subtenu el-tabs__active-bar width of the timing compensation task is incorrectly calculated, and only when the type of el-tabs is border-card or card will it appear.

What is Expected?

Modifying el-tabs__active-bar width

What is actually happening?

Width inconsistency