SemDedup bug fix for single element cluster

[praateekmahajan]

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Description

Without this that one single cluster will have datatype of int32 vs float32 for other columns and hence all of semdedup_pruning_tables won't be read in case some one tries to read it combined

Usage

# Add snippet demonstrating usage

Checklist

• [ ] I am familiar with the Contributing Guide.
• [ ] New or Existing tests cover these changes.
• [ ] The documentation is up to date with these changes.