Update Support L&R - Managing Product Issues workflow to use generic Support::Interest label

Why is this change being made?

Implement use of the SupportInterest labelling on all Fulfilment issues being prioritized by Support, to be used in addition to the Support Priority::1|2|3|4 to enable inclusion on different product boards and for reporting purposes.

• Request made in #support_licensing_root_cause
• Discussed in Sync on Support <> Provision 2023-03-16

This change can be applied without disruption, as per comment in the Create labeling scheme for issues and epics on the Support list for Fulfillment, we are no longer using the SupportInterest label in our current workflow.

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