fix(manager): removes outdated syncTarget field

[danwt]

PR Standards

Opening a pull request should be able to meet the following requirements

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Close #850

<-- Briefly describe the content of this pull request -->

For Author:

• Targeted PR against correct branch
• included the correct type prefix in the PR title
• Linked to Github issue with discussion and accepted design
• Targets only one github issue
• Wrote unit and integration tests
• All CI checks have passed
• Added relevant godoc comments

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For Reviewer:

• confirmed the correct type prefix in the PR title
• Reviewers assigned
• confirmed all author checklist items have been addressed

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After reviewer approval:

• In case targets main branch, PR should be squashed and merged.
• In case PR targets a release branch, PR should be rebased.

[omritoptix]

@danwt conflicts

[codecov]

Codecov Report

Attention: Patch coverage is 80.48780% with 8 lines in your changes are missing coverage. Please review.

Project coverage is 39.14%. Comparing base (851b312) to head (448db03).
Report is 33 commits behind head on main.

❗ Current head 448db03 differs from pull request most recent head 74ce466. Consider uploading reports for the commit 74ce466 to get more accurate results

Files	Patch %	Lines
block/synctarget.go	11.11%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #854      +/-   ##
==========================================
- Coverage   40.44%   39.14%   -1.31%     
==========================================
  Files         120      120              
  Lines       18935    18602     -333     
==========================================
- Hits         7659     7282     -377     
- Misses      10201    10281      +80     
+ Partials     1075     1039      -36     

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[omritoptix]

@danwt you may wanna change the filename of synctarget