[Spotless] Remove unused imports

[MitchellGale]

Description

Removes unused imports through spotless.

Note: This PR branch is based off #1926, so changes from 1926 will also show up here until 1926 is merged.

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #1927 (560681d) into main (d2de909) will not change coverage.
The diff coverage is n/a.

❗ Current head 560681d differs from pull request most recent head df888d6. Consider uploading reports for the commit df888d6 to get more accurate results

@@            Coverage Diff            @@
##               main    #1927   +/-   ##
=========================================
  Coverage     97.42%   97.42%           
  Complexity     4647     4647           
=========================================
  Files           408      408           
  Lines         11526    11526           
  Branches        839      839           
=========================================
  Hits          11229    11229           
  Misses          290      290           
  Partials          7        7           

Flag	Coverage Δ
sql-engine	97.42% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
...ain/java/org/opensearch/sql/analysis/Analyzer.java	100.00% <ø> (ø)
...alysis/DataSourceSchemaIdentifierNameResolver.java	100.00% <ø> (ø)
...rg/opensearch/sql/analysis/ExpressionAnalyzer.java	100.00% <ø> (ø)
...ensearch/sql/analysis/NamedExpressionAnalyzer.java	100.00% <ø> (ø)
...ecutor/streaming/MicroBatchStreamingExecution.java	100.00% <ø> (ø)
...c/main/java/org/opensearch/sql/expression/DSL.java	100.00% <ø> (ø)
...arch/sql/expression/datetime/DateTimeFunction.java	100.00% <ø> (ø)
...search/sql/planner/logical/LogicalFetchCursor.java	100.00% <ø> (ø)
...arch/sql/planner/physical/AggregationOperator.java	100.00% <ø> (ø)
.../sql/planner/physical/PhysicalPlanNodeVisitor.java	100.00% <ø> (ø)
... and 13 more