[Feat] Add column separators to `AgGrid` by default

[huong-li-nguyen]

Description

• Add column separators to AgGrid by default
• Replace screenshot in docs

Note: We should always remove the logo from the assets folder when doing screenshots for the docs, because that one doesn't exist in the folder for the user. So it shouldn't appear in the screenshots, as otherwise the results they will get differs from the screenshot.

Screenshot

Notice

• [x] I acknowledge and agree that, by checking this box and clicking "Submit Pull Request":

  • I submit this contribution under the Apache 2.0 license and represent that I am entitled to do so on behalf of myself, my employer, or relevant third parties, as applicable.
  • I certify that (a) this contribution is my original creation and / or (b) to the extent it is not my original creation, I am authorized to submit this contribution on behalf of the original creator(s) or their licensees.
  • I certify that the use of this contribution as authorized by the Apache 2.0 license does not violate the intellectual property rights of anyone else.
  • I have not referenced individuals, products or companies in any commits, directly or indirectly.
  • I have not added data or restricted code in any commits, directly or indirectly.