Remove `create_stubs: false` from droiddoc

`create_stubs: false` is the default behavior in soong as of
https://r.android.com/1380730

Test: m ahat-docs
Bug: 144248501
Bug: 143136634
Change-Id: If571c37c44af99988d8efac1f34a7a4d1bd7df20
1 file changed