Do not create syncer if already at stopnode

[gammazero]

No description provided.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 55.55556% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 54.07%. Comparing base (69d23c7) to head (bcf9245).

Files	Patch %	Lines
dagsync/subscriber.go	55.55%	3 Missing and 1 partial ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #173      +/-   ##
==========================================
+ Coverage   53.87%   54.07%   +0.19%     
==========================================
  Files          60       60              
  Lines        5041     5041              
==========================================
+ Hits         2716     2726      +10     
+ Misses       2028     2019       -9     
+ Partials      297      296       -1     

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