Update examples for Cloud Bigtable AppProfile

[modular-magician]

With latest cluster group support, users can create 3 different flavors of AppProfile:

Any cluster: requests can be routed to any of the clusters in an instance.
Single cluster: requests can be routed to the only cluster specified in the AppProfile.
Muti cluster: request can be routed to a group of clusters specified in the AppProfile.
Update the examples to show users can create all 3 different flavors of AppProfile mentioned above.

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bigtable: Update the examples to show users can create all 3 different flavors of AppProfile

Derived from GoogleCloudPlatform/magic-modules#5871

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