fix: fix analyze with 1 buckets

[L-maple]

What problem does this PR solve?

When unistore create a histogram, the bucket number should be less than or equal to the specified number.
But last_number = 0 causes the bucket number may exceed the specified number.

Issue Number: close #65439

Problem Summary:

What changed and how does it work?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

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None

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