fix: [2.4] Fix timeout when listing meta

[bigsheeper]

When there are too many key-value pairs, the etcd list operation may times out. This PR replaces LoadWithPrefix in list operations, which could involve many keys, with WalkWithPrefix.

issue: #37917

pr: #38151

[sre-ci-robot]

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[mergify]

@bigsheeper E2e jenkins job failed, comment /run-cpu-e2e can trigger the job again.

[bigsheeper]

/run-cpu-e2e

[codecov]

Codecov Report

Attention: Patch coverage is 69.07216% with 30 lines in your changes missing coverage. Please review.

Project coverage is 80.58%. Comparing base (febed0a) to head (3cb482a).
Report is 8 commits behind head on 2.4.

Files with missing lines	Patch %	Lines
internal/metastore/kv/datacoord/kv_catalog.go	75.75%	11 Missing and 5 partials ⚠️
internal/metastore/kv/querycoord/kv_catalog.go	54.83%	8 Missing and 6 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              2.4   #38216       +/-   ##
===========================================
+ Coverage   70.40%   80.58%   +10.17%     
===========================================
  Files        1074     1074               
  Lines      168099   168110       +11     
===========================================
+ Hits       118353   135471    +17118     
+ Misses      45291    28205    -17086     
+ Partials     4455     4434       -21     

Files with missing lines	Coverage Δ
internal/metastore/kv/querycoord/kv_catalog.go	65.63% <54.83%> (+0.32%)	⬆️
internal/metastore/kv/datacoord/kv_catalog.go	73.63% <75.75%> (-0.07%)	⬇️

... and 266 files with indirect coverage changes

[bigsheeper]

rerun ut