feat: add support for tags to the `newrelic_entity` data source

[abasha1234]

data_source_newrelic_entity

Fixes # issue-2666

In the GitHub issue linked above, it has been reported as feedback from a customer that the newrelic_entity data source in the New Relic Terraform Provider currently does not return the tags of the entity fetched. This PR will add support for tags to the data_source_newrelic_entity

[pranav-new-relic]

All other failures in integration tests seem to be expected because of latency, except

• TestAccNewRelicEntityData_RetrieveSubAccountEntity
• TestAccNewRelicEntityData_EntityInSubAccount

and these aren't working because the entity they're using in the referenced account no longer exists. I've just replenished the entity, and both of these tests shouldn't be failing from the next run.

[pranav-new-relic]

Replenished the dead entity again; rerunning integration tests