fix(optimizer): histogram calculations for string (Bytes) data types

[BohuTANG]

I hereby agree to the terms of the CLA available at: https://docs.databend.com/dev/policies/cla/

Summary

• Implements histogram calculations for string (Bytes) data types
• Adds type_name() method to Datum for better error messages
  old: Unsupported datum type: Bytes([56, 46, 48]), Bytes([57, 57, 57, 55])
  now: 1001=>Unsupported datum type for histogram calculation: 8.0 (type: String), 9997 (type: String). Only numeric types are supported.
• Enables accurate cardinality estimation for string predicates

Tests

• Unit Test
• Logic Test
• Benchmark Test
• [] No Test - Explain why

Type of change

• Bug Fix (non-breaking change which fixes an issue)
• New Feature (non-breaking change which adds functionality)
• Breaking Change (fix or feature that could cause existing functionality not to work as expected)
• Documentation Update
• Refactoring
• Performance Improvement
• [] Other (please describe): only add log

---

This change is 

[github-actions]

Docker Image for PR

• tag: pr-17873-e4691fc-1746008250

note: this image tag is only available for internal use.

[github-actions]

Docker Image for PR

• tag: pr-17873-8775f1a-1746019528

note: this image tag is only available for internal use.

[github-actions]

Docker Image for PR

• tag: pr-17873-248bfdf-1746022435

note: this image tag is only available for internal use.