Resolve dependency issues with ICON MCS example

[freemansw1]

While it is a phenomenal example, the ICON MCS notebook (https://tobac.readthedocs.io/en/latest/examples/Example_ICON_MCS_tracking/Example_ICON_MCS_tracking.html) currently has a few challenges requiring specific versions of various dependencies (e.g., intake, easygems) to work. We should try to find a way to update this notebook to be in line with the current versions of the dependencies and/or allow for soft failover.

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