[MINOR][STREAMING][DOCS] Minor changes on kinesis integration

## What changes were proposed in this pull request?

Some minor changes for documentation page "Spark Streaming + Kinesis Integration".

Moved "streaming-kinesis-arch.png" before the bullet list, not in between the bullets.

## How was this patch tested?

Tested manually, on my local machine.

Author: Xin Ren <iamshrek@126.com>

Closes #14097 from keypointt/kinesisDoc.