Fix query buffer resized test flakiness

[uriyage]

Fix query buffer resized correctly test by removing a flaky "after"
Failure example: https://github.com/valkey-io/valkey/actions/runs/9457340771/job/26050970622

*** [err]: query buffer resized correctly in tests/unit/querybuf.tcl
Expected 11 >= 16384 && 11 <= 32770 (context: type eval line 24 cmd {assert {$orig_test_client_qbuf >= 16384 && $orig_test_client_qbuf <= $MAX_QUERY_BUFFER_SIZE}} proc ::test)
*** [err]: query buffer resized correctly when not idle in tests/unit/querybuf.tcl
Expected 11 > 32768 (context: type eval line 14 cmd {assert {$orig_test_client_qbuf > 32768}} proc ::test)
*** [err]: query buffer resized correctly with fat argv in tests/unit/querybuf.tcl
query buffer should not be resized when client idle time smaller than 2s

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.22%. Comparing base (b546dd2) to head (200cb3a).

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable     #646      +/-   ##
============================================
- Coverage     70.22%   70.22%   -0.01%     
============================================
  Files           110      110              
  Lines         60039    60039              
============================================
- Hits          42163    42160       -3     
- Misses        17876    17879       +3     

see 9 files with indirect coverage changes

[enjoy-binbin]

LGTM, please fix the DCO