action: fix benchmark on schedule without cache will panic

[Desiki-high]

When we can't find the last benchmark result cache, the workfolow will panic.So we should cover the case when we can't find cache.

• no cache: https://github.com/dragonflyoss/image-service/actions/runs/4899401706/attempts/1#summary-13278927308
• find cache: https://github.com/dragonflyoss/image-service/actions/runs/4899401707#summary-13278921048

[codecov]

Codecov Report

Merging #1262 (e518e0b) into master (6d1d56e) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1262   +/-   ##
=======================================
  Coverage   45.06%   45.06%           
=======================================
  Files         126      126           
  Lines       37395    37395           
  Branches    37395    37395           
=======================================
  Hits        16851    16851           
+ Misses      19656    19652    -4     
- Partials      888      892    +4     

see 3 files with indirect coverage changes

[anolis-bot]

@Desiki-high , the title has been updated, so a new test job has been submitted. Please wait in patience. The test job url: https://tone.openanolis.cn/ws/nrh4nnio/test_result/71214

[anolis-bot]

@Desiki-high , The CI test is completed, please check result:

Test Case		Test Result
build rust golang image		✅ SUCCESS
compile nydusd		✅ SUCCESS
compile ctr remote		✅ SUCCESS
compile nydus snapshotter		✅ SUCCESS
run container with rafs		✅ SUCCESS
run container with zran		✅ SUCCESS
run container with rafs and compile linux		✅ SUCCESS

Congratulations, your test job passed!

[imeoer]

LGTM!