tests: make e2e TestBasicSuspension less flaky

[algorandskiy]

Summary

Failure:

    fixture.go:120: 
        	Error Trace:	/opt/cibuild/project/test/e2e-go/features/incentives/suspension_test.go:122
        	Error:      	Not equal: 
        	            	expected: 0x0
        	            	actual  : 0x1
        	Test:       	TestBasicSuspension

Fix is to sync all test clients before proceeding, the same idea as #5986

Test Plan

This is a test fix

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.90%. Comparing base (6c91f52) to head (3ef0cb7).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5995      +/-   ##
==========================================
- Coverage   55.94%   55.90%   -0.05%     
==========================================
  Files         482      482              
  Lines       68310    68310              
==========================================
- Hits        38219    38189      -30     
- Misses      27500    27523      +23     
- Partials     2591     2598       +7     

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