Revert changes to test_requirements.txt and requirements.txt once Kedro 0.19 releases

[SajidAlamQB]

Description

Following starters work, #159, we switched to using the develop branch in test_requirements.txt so starters could use the new add-ons flow from kedro and unblock development. This also meant we had to update kedro-viz to work with develop so we had to point all requirments.txt from starters to the kedro-viz main repo instead of PyPi.

Once Kedro 0.19.0 and next release of Kedro-Viz is out we can revert these back to the default settings.

• Revert kedro to using the main branch in test_requirements.txt in framework.
• Revert kedro-viz pin in requirments.txt to point to the release version (PyPi).

[merelcht]

Completed in #194