fix(integration): prevent flaky connector sink tests from f64 round-trip mismatch

[hubcio]

The serde_json (Ryu) and simd_json serializers format
non-exact f64 values differently. Multiplying by 99.99
produced values like 1099.89 that round-tripped as
1099.8899999999999 through the connector SDK's
simd_json path, causing assertion failures in Quickwit
sink tests.

Multiplying by 100.0 produces exact integers (0.0,
100.0, 200.0, ...) that all IEEE 754 serializers
represent identically.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.68%. Comparing base (71eb4d5) to head (8fa5304).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2838      +/-   ##
============================================
+ Coverage     67.66%   67.68%   +0.02%     
  Complexity      708      708              
============================================
  Files          1030     1030              
  Lines         83846    83846              
  Branches      60704    60704              
============================================
+ Hits          56733    56751      +18     
+ Misses        24765    24746      -19     
- Partials       2348     2349       +1     

Flag	Coverage Δ
rust	69.72% <ø> (+0.03%)	⬆️

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see 6 files with indirect coverage changes

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