docs: Release notes for 0.19.3

[Dan-Heath]

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This PR updates the 0.19.x release notes for the upcoming 0.19.3 release. It contains the following updates, click the links to see them in the preview deployment:

• Added an item to the Important changes table to explain that redundant grant scopes are no longer permitted.
• Added an item to the Known issues section to explain the command to remove redundant grant scopes and the reason for the change
• Added the Feature deprecations section and included the 2 command options we are deprecating in this version