fix: fix the issue where the license may be an object

[Beace]

有些 package 的 license 是个对象，会导致 es 写入失败 https://github.com/cnpm/cnpmcore/issues/585#issuecomment-1706009496

[codecov[bot]]

Codecov Report

Merging #587 (79a98e5) into master (89f6b98) will decrease coverage by 0.06%. Report is 1 commits behind head on master. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #587      +/-   ##
==========================================
- Coverage   96.99%   96.94%   -0.06%     
==========================================
  Files         180      180              
  Lines       17360    17365       +5     
  Branches     2255     2251       -4     
==========================================
- Hits        16838    16834       -4     
- Misses        522      531       +9     

Files Changed	Coverage Δ
app/core/service/PackageSearchService.ts	93.83% <100.00%> (ø)
app/repository/PackageRepository.ts	98.22% <100.00%> (+0.01%)	:arrow_up:

... and 2 files with indirect coverage changes