Dashboard Scene: Improve Save/Discard Buttons interactions

[axelavargas]

We got feedback about our save/discard interactions, currently it is confusing to our users.

For instance:

• Go to a dashboard with a panel created
• Change the description of the panel.
• The save button is blue and users can save the changes
• Although the changes are now saved, there is a red button Discard panel changes (it does not do anything)

There are more scenarios about this confusing interaction. To fix this issue you can take a look at the expected behaviours in this figma file.