Allow user to disable top toast message when changing terminal sessions

[thunder-coding]

The top toast message when changing terminal sessions can be useful as well as irritating sometimes.

When using a terminal code editor, it can be especially irritating as it hides the text behind it for almost 1.5s.

Proposed solution

• Allow user to disable the toast message by setting a display-toast-on-session-change to false (should default to true)