fix: Set filter selectivity estimate lower bound

[colin-ho]

Set filter selectivity estimate lower bound to 1%, to prevent overly selective and likely inaccurate estimations.

[codspeed-hq]

CodSpeed Performance Report

Merging #3694 will improve performances by 10.71%

_{Comparing colin/selectivity-lower-bound (672396e) with main (4b67e5a)}

Summary

⚡ 1 improvements
✅ 26 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	colin/selectivity-lower-bound	Change
⚡	test_count[1 Small File]	3.7 ms	3.4 ms	+10.71%

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.85%. Comparing base (4b67e5a) to head (672396e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3694   +/-   ##
=======================================
  Coverage   77.84%   77.85%           
=======================================
  Files         732      732           
  Lines       90605    90608    +3     
=======================================
+ Hits        70534    70541    +7     
+ Misses      20071    20067    -4     

Files with missing lines	Coverage Δ
src/daft-dsl/src/expr/mod.rs	76.00% <100.00%> (+0.02%)	⬆️

... and 2 files with indirect coverage changes