[minor]Fix ci clippy for unused import

[Ted-Jiang]

Which issue does this PR close?

Block current Pr

 Checking datafusion-common v8.0.0 (/__w/arrow-datafusion/arrow-datafusion/datafusion/common)
    Checking datafusion-expr v8.0.0 (/__w/arrow-datafusion/arrow-datafusion/datafusion/expr)
    Checking datafusion-row v8.0.0 (/__w/arrow-datafusion/arrow-datafusion/datafusion/row)
    Checking datafusion-physical-expr v8.0.0 (/__w/arrow-datafusion/arrow-datafusion/datafusion/physical-expr)
    Checking datafusion-jit v8.0.0 (/__w/arrow-datafusion/arrow-datafusion/datafusion/jit)
    Checking datafusion v8.0.0 (/__w/arrow-datafusion/arrow-datafusion/datafusion/core)
error: unused import: `union_with_alias`
  --> datafusion/core/src/sql/planner.rs:32:5
   |
32 |     union_with_alias, Column, CreateCatalog, CreateCatalogSchema,
   |     ^^^^^^^^^^^^^^^^
   |
   = note: `-D unused-imports` implied by `-D warnings`

error: could not compile `datafusion` due to previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `datafusion` due to previous error

Closes #.

Rationale for this change

What changes are included in this PR?

Are there any user-facing changes?

[Ted-Jiang]

@alamb @andygrove FYI

[Ted-Jiang]

Block #2580

[alamb]

I think this might be a dupe of #2585