[Data] Skip execution for LogicalPlans with only InputData op

[scottjlee]

Why are these changes needed?

• After [Data] Enable read-only Datasets to be executed on new execution backend #41466, all Datasets are executed using the new streaming executor backend. There is an edge case that was not caught related to MaterializedDatasets, where executing the already materialized dataset caused extraneous (empty) metrics to be registered from these newly created datasets. This PR covers this edge case by skipping execution in the case where the Dataset's logical plan consists of only an InputData operator.
• Also enables Data dashboard tests to run for any data-related change, not just for dashboard related changes.

Related issue number

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• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
  • I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[aslonnie]

I will force merge this for you.

[c21]

Late LGTM.