feat: Enable bucket pruning with native_datafusion scans

[mbutrovich]

Which issue does this PR close?

Closes #1719.

Rationale for this change

What changes are included in this PR?

If this partition's list of files is empty, use DataFusion's EmptyExec instead of instantiating a DataSourceExec.

How are these changes tested?

New test. CometExecSuite runs with CometConf.COMET_NATIVE_SCAN_IMPL.key -> CometConf.SCAN_AUTO but I set it to SCAN_NATIVE_DATAFUSION and confirmed that it was using the fully-native scan and passed the test.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 59.43%. Comparing base (f09f8af) to head (17876f7).
⚠️ Report is 758 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2888      +/-   ##
============================================
+ Coverage     56.12%   59.43%   +3.31%     
- Complexity      976     1376     +400     
============================================
  Files           119      167      +48     
  Lines         11743    15335    +3592     
  Branches       2251     2548     +297     
============================================
+ Hits           6591     9115    +2524     
- Misses         4012     4935     +923     
- Partials       1140     1285     +145     

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[andygrove]

Could you also update contributor-guide/parquet_scans.html

[andygrove]

Nice! Thanks @mbutrovich

[comphead]

Thanks @mbutrovich one more limitation is gone