log: change log level to reduce the noise logs

[chlins]

1. Change some logs level to reduce the noise.
2. Wrap the go-redis.Nil error as ErrNotFound to avoid confusing

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Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

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• Well Written Title and Summary of the PR
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[codecov]

Codecov Report

Merging #19146 (8517773) into main (d98699b) will increase coverage by 0.02%.
The diff coverage is 57.14%.

@@            Coverage Diff             @@
##             main   #19146      +/-   ##
==========================================
+ Coverage   67.40%   67.43%   +0.02%     
==========================================
  Files         993      993              
  Lines      108864   108866       +2     
  Branches     2751     2751              
==========================================
+ Hits        73377    73411      +34     
+ Misses      31539    31511      -28     
+ Partials     3948     3944       -4     

Flag	Coverage Δ
unittests	67.43% <57.14%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/core/session/session.go	34.82% <0.00%> (ø)
src/server/registry/manifest.go	66.90% <0.00%> (ø)
src/lib/cache/redis/redis.go	71.30% <100.00%> (-0.38%)	⬇️
src/pkg/notifier/notifier.go	82.35% <100.00%> (ø)

... and 10 files with indirect coverage changes

[wy65701436]

lgtm