Add Initialize method to HangfireBackgroundWorkerManager

[realLiangshiwei]

Description

Resolves #18477

Checklist

• I fully tested it as developer / designer and created unit / integration tests
• I documented it (or no need to document or I will create a separate documentation issue)

[codecov]

Codecov Report

Attention: 7 lines in your changes are missing coverage. Please review.

Comparison is base (562fcee) 51.93% compared to head (a42b061) 51.93%.
Report is 22 commits behind head on rel-7.4.

Files	Patch %	Lines
...o/Abp/Identity/AbpIdentityResultException_Tests.cs	0.00%	7 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           rel-7.4   #18478   +/-   ##
========================================
  Coverage    51.93%   51.93%           
========================================
  Files         3024     3024           
  Lines        94448    94455    +7     
  Branches      7516     7516           
========================================
+ Hits         49054    49058    +4     
- Misses       43907    43912    +5     
+ Partials      1487     1485    -2     

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