Remove method AvailableServices#free_access?

What does this MR do and why?

Removes method AvailableServices#free_access?. We are retiring this class and all its uses.

The functionality to check for "free access" is now instead expressed in terms of local helpers, with the same logic as before i.e. based on the "cut-off date". Over time, we will replace these with a new implementation that will allow to test for add-on requirements based on the add_ons array in any given UP: Replace "free access" logic with "requires add-on" (#554551)

Not user-facing.

References

#542420 (closed)

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Related to #542420 (closed)