Fix master compile: missing IOException import in TableConfigsRestletResourceTest

[yashmayya]

Summary

• PR Add POST /tableConfigs/tune endpoint to apply tuning and return tuned config #18056 added throws IOException to a new test method testTuneConfig() in TableConfigsRestletResourceTest without importing java.io.IOException, breaking the master test-compile.
• Adds the missing import.

Test plan

• ./mvnw test-compile -pl pinot-controller passes locally.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.73%. Comparing base (9471163) to head (1f28b72).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #18536      +/-   ##
============================================
+ Coverage     55.76%   63.73%   +7.97%     
- Complexity      815     1930    +1115     
============================================
  Files          2561     3292     +731     
  Lines        148577   201519   +52942     
  Branches      24019    31322    +7303     
============================================
+ Hits          82850   128434   +45584     
- Misses        58624    62795    +4171     
- Partials       7103    10290    +3187     

Flag	Coverage Δ
custom-integration1	100.00% <ø> (?)
integration	100.00% <ø> (?)
integration1	100.00% <ø> (?)
integration2	0.00% <ø> (?)
java-21	63.73% <ø> (+7.97%)	⬆️
temurin	63.73% <ø> (+7.97%)	⬆️
unittests	63.72% <ø> (+7.96%)	⬆️
unittests1	55.75% <ø> (-0.01%)	⬇️
unittests2	35.26% <ø> (?)

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