[webapi]Update the component attribute in the tests*.xml files of webapi packages

@jiajiax @jennycao do we have any requirement for removing these 2 lines?

```
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="./testcase.xsl"?>
```

Without them, browser will out warning when open this file:

> This XML file does not appear to have any style information associated with it. The document tree is shown below.